Step 1: Understanding the Question:
We need to identify which organisation D R Mehta headed as its former chairman.
Step 2: Key Formula or Approach:
This is a recall based question about Indian regulatory bodies, so we match the person's name with the institution he led.
Step 3: Detailed Explanation:
D R Mehta was the Chairman of the Securities and Exchange Board of India (SEBI) from 1995 to 2002, and is credited with strengthening SEBI's regulatory powers after the 1992 securities scam.
SBI (State Bank of India) is headed by a Chairman as well, but D R Mehta was never associated with SBI in that role, so option (1) is wrong.
Maruti Udyog Ltd is an automobile company and its chairmen have come from the Suzuki and Indian government side, not D R Mehta, so option (2) is wrong.
Since SEBI is listed as an option, option (4), none of these, does not apply.
Step 4: Final Answer:
D R Mehta was the former chairman of SEBI, so the answer is option (3).