The correct answer is option 'C' - Brigadier Gyan Singh.

Explanation:
- The Adventure course of mountaineering is a specialized training program for individuals interested in mountaineering and adventure sports.
- It is important to note that the given options include various individuals who have excelled in different fields, but only one of them is directly associated with the Adventure course of mountaineering.
- Let's analyze each option to understand why option 'C' is the correct answer:
- Option 'A' - Milkhasingh: Milkhasingh is a renowned Indian athlete who excelled in the sport of track and field. However, he is not associated with mountaineering or adventure courses.
- Option 'B' - Bachhendripal: The name Bachhendripal is not widely recognized, and there is no known association with mountaineering or adventure courses.
- Option 'C' - Brigadier Gyan Singh: Brigadier Gyan Singh is a well-known name in the field of mountaineering. He was the Director of the Adventure course of mountaineering, which indicates his direct involvement in the training program.
- Option 'D' - Dhyan Singh: Dhyan Singh is a common name and does not have any known association with mountaineering or adventure courses.
- Therefore, based on the analysis, option 'C' - Brigadier Gyan Singh is the correct answer as he was the Director of the Adventure course of mountaineering.

In conclusion, the correct answer to the question "Who was the director of Adventure course of mountaineering?" is option 'C' - Brigadier Gyan Singh. He played a significant role in overseeing the training program and guiding individuals interested in mountaineering and adventure sports.

[Brigadier Gyan Sing] was the director of (Advanture course of mountaineering)