Bhawana Kanth, Avani Chaturvedi, and Mohana Singh are fighter pilots. Fighter pilots are highly skilled individuals who operate and control military aircraft. They undergo extensive training in order to fly and engage in combat missions.

Option 1, sprinters, refers to athletes who compete in short-distance running events, which is not relevant to the given individuals.

Option 2, rock climbers, are individuals who climb mountains and cliffs using specialized equipment and techniques. While it is possible for fighter pilots to have hobbies such as rock climbing, it is not their primary profession.

Option 4, mountaineers, are individuals who climb mountains as a sport or as a profession. Again, while fighter pilots may have an interest in mountaineering, it is not their primary occupation.

In conclusion, Bhawana Kanth, Avani Chaturvedi, and Mohana Singh are fighter pilots, not sprinters, rock climbers, or mountaineers.