Explanation:

- The book "The Naked Triangle" is not the autobiography of Balraj Sahni.

- Balraj Sahni (Option 1) wrote his autobiography titled "Meri Filmi Aatmakatha" (My Film Autobiography).

- Balwant Gargi (Option 2) is the correct answer. He was a famous Punjabi playwright and novelist, and "The Naked Triangle" is his well-known autobiography.

- Jaswant Singh Kanwal (Option 3) was a well-known Punjabi novelist, but "The Naked Triangle" is not linked to him.

- Kartar Singh Duggal (Option 4) was a prominent Punjabi and Urdu writer, not the author of this book.