Explanation:

- Sarnath: This is where Gautama Buddha delivered his first sermon, known as the Dhammacakkappavattana Sutta, after attaining enlightenment. It is a significant pilgrimage site for Buddhists around the world.

- Barabar Caves: These are some of the earliest rock-cut caves in India but not directly associated with Buddha’s first sermon. They are known for their polished surfaces and historical significance during the Maurya Empire.

- Kushinagar: This is where Gautama Buddha is believed to have attained Parinirvana, the end of the cycle of birth and rebirth.

- Bodh Gaya: Here, under the Bodhi tree, Gautama Buddha attained enlightenment. It is one of the four main pilgrimage sites related to his life.

The correct answer is: Option 2: Sarnath

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