The correct answer is A. 1945.
India became a founding member of the United Nations on 24 October 1945, along with 50 other countries. The UN was established after the Second World War to promote international co-operation and to prevent future conflicts. India has played a significant role in the UN, serving as a non-permanent member of the Security Council on 10 occasions. India is also a member of a number of UN specialized agencies, including the World Bank, the International Monetary Fund, and the World Health Organization.
Option B, 1947, is incorrect because India gained independence from British rule on 15 August 1947.
Option C, 1959, is incorrect because China became a member of the UN in that year.
Option D, 1960, is incorrect because 18 new countries joined the UN in that year, including 16 African countries.