King Harshavardhana wrote the famous Sanskrit play ……. .

The correct answer is: C. Nagananda

King Harshavardhana was a 7th-century Indian emperor who ruled over the northern Indian subcontinent. He was a patron of the arts and literature, and is credited with writing several Sanskrit plays, including Nagananda.

Nagananda is a play about the love between a monkey and a human princess. It is considered to be one of the finest examples of Sanskrit literature.

The other options are incorrect. Bharatanjali is a treatise on Sanskrit grammar, written by Panini. Narayaniyan is a poem about the Hindu god Vishnu, written by Vyasa. None of these works are plays.