Looking at our answer choices, there are four types of sentences:

1. A declarative sentence is a sentence that tells the reader about something, and it will always end with a period.
2. An imperative sentence is a sentence that is a command, it tells someone to do something. This type of sentence will end in either a period or an exclamation point. 
3. An interrogative sentence is a sentence that asks something, it's a question. This type of sentence will always end with a question mark.
4. An exclamatory sentence is a sentence that shows excitement, surprise, or a strong emotion. This type of sentence will always end with an exclamation point.

Let's look at the sentence from the question:

I just got a puppy!

This sentence is ends in an explanation. This is an exclamatory sentence. 

Looking at our answer choices, there are four types of sentences:

1. A declarative sentence is a sentence that tells the reader about something, and it will always end with a period.
2. An imperative sentence is a sentence that is a command, it tells someone to do something. This type of sentence will end in either a period or an exclamation point. 
3. An interrogative sentence is a sentence that asks something, it's a question. This type of sentence will always end with a question mark.
4. An exclamatory sentence is a sentence that shows excitement, surprise, or a strong emotion. This type of sentence will always end with an exclamation point.

Let's look at the sentence from the question:

I got an A on the test!

This sentence is ends in an explanation. This is an exclamatory sentence. 

Of our answer choices, "September" should be capitalized because it's a month and months are always capitalized. "Dog", "bark", and "run" would only need to be capitalized if they were at the beginning of a sentence. 

Of our answer choices, "Eric" should be capitalized because it's a name and names are always capitalized. "Cat", "blanket", and "toy" would only need to be capitalized if they were at the beginning of a sentence. 

Of our answer choices, "December" should be capitalized because it's a month and months are always capitalized. "Happy", "cat", and "jump" would only need to be capitalized if they were at the beginning of a sentence. 

Of our answer choices, "Sarah" should be capitalized because it's a name and names are always capitalized. "Flag", "grass", and "car" would only need to be capitalized if they were at the beginning of a sentence. 

"May" is a month, and months should always be capitalized. The other words would only need to be capitalized if they were the first word of a sentence. 

"January" is a month, and months should always be capitalized. The other words would only need to be capitalized if they were the first word of a sentence. 

"April" is a month, and months should always be capitalized. The other words would only need to be capitalized if they were the first word of a sentence. 

Of our answer choices, "Brian" should be capitalized because it's a name and names are always capitalized.  The other words would only need to be capitalized if they were the first word of a sentence.