Among the following Presidents of India, who was also the Secretary General of Non-Aligned Movement for some period ?

The correct answer is Option 3 (Giani Zail Singh).

Giani Zail Singh, the seventh President of India (1982–1987), served as the Secretary-General of the Non-Aligned Movement (NAM) from 1983 to 1986. This occurred because India hosted the 7th NAM Summit in New Delhi in 1983. By convention, the post of Secretary-General is held by the Head of State or Government of the host country. While Prime Minister Indira Gandhi and later Rajiv Gandhi were the active political faces, Giani Zail Singh held the formal position as the Head of State.

• Dr. S. Radhakrishnan and V.V. Giri served before India hosted a NAM summit.
• Dr. Shanker Dayal Sharma served as President (1992–1997) long after India's chairmanship had concluded.

Therefore, Giani Zail Singh is the only Indian President to have held this prestigious international administrative role during his tenure.