Who is the author of “Annihilation of Caste”?

Who is the author of the book “Discovery of India”?

Who was the author of Indian Unrest?

Who is the author of the book 'A Gallery of Rascals'?

Who is the author of the famous book 'Gulamgiri' ?

Who of the following is the author of a collection of a poem called ‘ Golden Threshold’?