The correct answer is C. New York.
The United Nations Population Fund (UNFPA) is an international agency that provides financial and technical assistance to developing countries with the goal of improving reproductive health and reducing poverty. UNFPA was founded in 1969 and is headquartered in New York City.
The other options are incorrect. London is the capital of the United Kingdom and the seat of the British government. Washington, D.C. is the capital of the United States and the seat of the U.S. government. Rome is the capital of Italy and the seat of the Catholic Church.