Step 1: Understanding the Concept:
The question asks to identify which of the plays in the list were written by the eminent Indian playwright Girish Karnad.
Step 2: Detailed Explanation:
Girish Karnad was a prolific and celebrated playwright, and all the plays listed are among his most famous works.
- (A) Tughlaq: A historical play about the Sultan Muhammad bin Tughlaq.
- (B) Yayati: His debut play, based on a myth from the Mahabharata.
- (C) Nagamandala: A play based on two folk tales from Karnataka.
- (D) Hayavadana: A play inspired by Thomas Mann's The Transposed Heads, which itself was based on an ancient Indian story.
All four are major plays in Girish Karnad's oeuvre.
Step 3: Final Answer:
All the plays listed—Tuglak, Yayati, Nagamandala, and Hayavadana—were written by Girish Karnad.