The correct answer is Bhagavad Gita.
Sagan was a student of religion. After he read the Bhagavad Gita, he decided to go on a spiritual quest.
The Bhagavad Gita is an important sacred text of the Hindus. It is part of the famous Hindu text called the Mahabharata. It is written in Sanskrit. It relates the story of Prince Arjuna of Pandava and Krishna, his guide. The story tells moral concepts when confronted with moral dilemmas and decision-making. The Bhagavad Gita invites to follow the four paths of Hindu spirituality.