Explanation:

Here’s the breakdown:

- Option 1: Mukesh Ambani

Mukesh Ambani, chairman of Reliance Industries, held the title of India’s richest person for several years. His wealth mainly comes from oil, petrochemicals, telecom, and retail businesses.

- Option 2: Poonawalla

Cyrus Poonawalla, known for Serum Institute, is one of India’s richest, but his net worth didn’t top Mukesh Ambani’s as of April 2022.

- Option 3: Nadar

Shiv Nadar, founder of HCL Technologies, is a major IT billionaire, but again, not as wealthy as Ambani at that time.

- Option 4: Adani

Gautam Adani saw a major leap in net worth in 2022 and edged past Ambani around April 2022, becoming India's richest person then.

The correct answer is:

Option 4: Adani