"Delusions of grandeur" is the correct answer. Delusions of grandeur are fixed, false beliefs that oneself is superior (e.g. in fame, wealth, omnipotence, power). While this is a form of hallucination, the most correct answer is delusions of grandeur.

Although "social isolation" may occur in individuals with schizophrenia, the other answer choices are widely accepted symptoms of schizophrenia that are assessed by mental health practitioners when making a schizophrenia diagnosis. In other words, social isolation in and of itself is not indicative of schizophrenia. 

Ms. Johnson presents symptoms characterized by hallucinations and delusions—two hallmark symptoms of "schizophrenia." Schizophrenia is a severe psychiatric illness in which people have trouble distinguishing fantasy from reality. Among women, schizophrenia typically begins in the late 20s.

Schizophrenia is a mental disorder hallmarked by "psychosis" - losing touch with reality. The major neurotransmitter implicated in this disorder is dopamine. Imbalances in dopamine are responsible for the positive and negative symptoms of schizophrenia.

One of the characteristics of speech of the paranoid person is disorganized ranting. There is no logical sequence to what's being said and it will often sound like the person is speaking to or of an imaginary entity. The speech is often tangential and off-topic.

Works Cited:

U.S. Department of Health and Human Services. Mental Health: A Report of the Surgeon General. Rockville, MD: U.S. Department of Health and Human Services, Substance Abuse and Mental Health Services Administration, Center for Mental Health Services, National Institutes of Health, National Institute of Mental Health, 1999. (https://profiles.nlm.nih.gov/ps/access/NNBBHS.pdf).

All of the choices represent manifestations of disorganized thoughts in the speech associated with a paranoid schizophrenia. This described as "disorganized speech" and represents a symptom that is characteristic of paranoid schizophrenia. "Tangentiality" is steering away from the topic at hand. For instance: 

Q: Have you been nervous or tense lately?

A: No, I got a head of lettuce.

"Derailment" occurs when the topic is constantly being changed. If asked whether or not they like TV, then a paranoid schizophrenic might respond with "My sister likes TV. I dance to what's on the TV. I like to draw and read stories." The patient can also cleverly coin new terms on the spot, which are called "neologisms." Last, excessive rhyming or almost poetic-like speech is calling "clanging." 

All of the answer choices represent cognitive symptoms commonly associated with paranoid schizophrenia (i.e. symptoms regarding thinking, focus, and memory). Negative cognitive symptoms include a lack of concentration, memory, and an inability to express one's thoughts. On the other hand, positive cognitive symptoms include disorganized thinking that is generally chaotic and irrational.

Works Cited:

U.S. Department of Health and Human Services. Mental Health: A Report of the Surgeon General. Rockville, MD: U.S. Department of Health and Human Services, Substance Abuse and Mental Health Services Administration, Center for Mental Health Services, National Institutes of Health, National Institute of Mental Health, 1999. (https://profiles.nlm.nih.gov/ps/access/NNBBHS.pdf).

Positive symptoms are defined as behaviors or patterns that are "added" to an individual possessing a mental disorder as opposed to symptoms that are taken away. "Affective flattening," "avolition," and "alogia" are all defined by the absence of certain aspects of cognition that a non-affected person would possess. On the other hand, "hallucinations," that is distortions in perception of what is real, are a positive symptom of paranoid schizophrenia. 

Works Cited:

U.S. Department of Health and Human Services. Mental Health: A Report of the Surgeon General. Rockville, MD: U.S. Department of Health and Human Services, Substance Abuse and Mental Health Services Administration, Center for Mental Health Services, National Institutes of Health, National Institute of Mental Health, 1999. (https://profiles.nlm.nih.gov/ps/access/NNBBHS.pdf).

Alogia can be one of the symptoms that paranoid schizophrenic experiences. It is a negative symptom characterized by a lack of language production as a result of "blocked thought." This is often manifested in short, empty phrases.

Delusions are firmly held erroneous beliefs that are a product of distortions or exaggerations of reasoning and/or misinterpretations of perceptions or experiences. When someone has paranoid schizophrenia, delusions of being followed or watched are common; furthermore, those suffering from this disorder may believe that radio or TV programs are sending them special messages. This is paranoid thinking, which is the identifying pattern of the illness. It creates a world for the affected person where everyone is "out to get them."

Works Cited:

U.S. Department of Health and Human Services. Mental Health: A Report of the Surgeon General. Rockville, MD: U.S. Department of Health and Human Services, Substance Abuse and Mental Health Services Administration, Center for Mental Health Services, National Institutes of Health, National Institute of Mental Health, 1999. (https://profiles.nlm.nih.gov/ps/access/NNBBHS.pdf).