Explanation:

- Gurucharan Das: He is an Indian author and management guru known for works like 'India Unbound'. But he is not the author of 'Democrats and Dissenters'.

- Ramchandra Guha: He is a renowned Indian historian and writer. He authored the book 'Democrats and Dissenters', which explores varied topics in Indian politics and society.

- Nalini Singh: She is an Indian journalist and author known for her media presence, but she has not written 'Democrats and Dissenters'.

- Arun Shourie: An Indian economist, journalist, and politician, Arun Shourie has authored several books, but not 'Democrats and Dissenters'.