The correct answer is option 4: 35 years. To become the Prime Minister of India, an individual must meet certain eligibility criteria, one of which is the minimum age requirement. The Indian Constitution specifies that a person must be at least 35 years old to hold the position of the Prime Minister. This age requirement ensures that candidates possess sufficient life and professional experience before assuming such a high-level role in the government. It is important to note that this age requirement is specific to the position of the Prime Minister and may differ from the minimum age requirements for other political positions in India.