The oldest religious documents in the world are the Rig Veda, the earliest scriptures in the Hindu tradition. These were composed somewhere between 2000 BCE and 1000 BCE in the Indus River Valley, in modern day Pakistan. The Vedic culture would come to dominate the northern Indian subcontinent by 1400 BCE, spreading the religion that would evolve into present forms of Hinduism.

The Mahabharata is an epic poem that chronicles the Kurukshetra War between the Kaurava and Pandava princes. As well as being a history, the text contains many philosophical passages, including the Bhagavad Gita. These devotional texts make the Mahabharata an extremely important text for Hinduism.

The idea of reincarnation—that people are reborn into different bodies after they die—is part of both Hinduism and Buddhism. All of the other answer choices are incorrect because they contain at least one religion that did not include the idea of reincarnation.

Rama and Krishna are avatars in the Hindu religion.

Mahabharata and Ramayana are two very famous Indian Epic Poems written in approximately the fourth century B.C.E. that form an important part of Hindu religious and culutral tradition. The Epic of Rama remains particularly important in Indian society where Rama is often employed for political or economic motivations. 

The Vedas are four books that collectively serve as a guide for life and a manual for performing spiritual rituals in the Hindu religion. They were originally written in Sanskrit, the language of Ancient and Classical India. They remain widely influential to this day. 

Reincarnation is the belief that after you die your soul will move on to a new form, usually depending on what kind of life you have led. So in the Hindu tradition a very virtuous and righteous man might go to heaven, a good and honest man might return to Earth in the form of a new human, a dishonest and sinful man might return to Earth in the form of a plant or an animal, and a wicked and depraved man might be condemned to hell. All of the Abrahamic religions - Judaism, Christianity, and Islam - do not believe in the tenet of reincarnation. But, it is central to many other religions including Hinduism, Buddhism, and Jainism. 

Confucianism, originated by the Chinese philosopher Kung Fu Tzu in the sixth century BCE, is largely an ethical teaching that preaches devotion to family, order, and authority. While immensely popular on its own, it became the state philosophy and quasi-religion under the Han Dynasty (206 BCE-220 CE). Confucianism's devotion to order and authority became important teaching tools for the Emperor.

The four noble truths were taught by Buddha and are an important part of Buddhism. None of the religions listed in the other answer choices includes the four noble truths.

Filial piety is the complete obedience to one's parents, ancestors, and elders in society. It was a central tenet of the Chinese religion/philosophy of Confucianism.