Where is the headquarters of Pan American Health Organization?

The correct answer is A. Washington DC.

The Pan American Health Organization (PAHO) is a regional office of the World Health Organization (WHO) that serves the Americas. It is headquartered in Washington, D.C., United States. PAHO works to improve the health and well-being of the people of the Americas by providing technical support, training, and information to governments and other partners. It also conducts research and promotes public health policies.

Option B, Ottawa, is the capital of Canada. Option C, New York, is the most populous city in the United States. Option D, Mexico, is a country in North America.