Explanation:

- P Chidambaram: He is an Indian politician who served as the Union Minister of Finance and as the Minister of Home Affairs but isn't associated with "Karmayodha Granth."

- Amit Shah: He is the current Union Minister of Home Affairs and released the book "Karmayodha Granth" in New Delhi.

- Sushilkumar Shinde: Another former Union Minister of Home Affairs, known for his tenure during the UPA government, but not linked to the book.

- Rajnath Singh: Previously held the position of Union Minister of Home Affairs, but not related to this specific book release.

Thus, Amit Shah is the correct answer.