The correct answer is (d) Sushil Kumar.
Sushil Kumar is an Indian freestyle wrestler who competes in the 66 kg category. He is a two-time Olympic medalist, a four-time world champion, and a seven-time Asian champion. He is the first Indian wrestler to win a gold medal at the Olympics. He is also the first Indian wrestler to win a medal at the World Championships.
Anil Kumar is an Indian freestyle wrestler who competes in the 57 kg category. He is a two-time Commonwealth Games gold medalist and a two-time Asian Games silver medalist. He is also a two-time World Championship bronze medalist.
Rajendra Kumar is an Indian freestyle wrestler who competes in the 61 kg category. He is a two-time Commonwealth Games silver medalist and a two-time Asian Games bronze medalist. He is also a two-time World Championship bronze medalist.
Ravinder Singh is an Indian freestyle wrestler who competes in the 74 kg category. He is a Commonwealth Games gold medalist and a World Championship bronze medalist.
Anil Kumar, Rajendra Kumar, and Ravinder Singh are all accomplished wrestlers, but Sushil Kumar is the only Indian wrestler to have won a gold medal at the Olympics. He is also the only Indian wrestler to have won a medal at the World Championships.