Concept:Air masses are classified by their source region and moisture content.Explanation:The Tropical maritime airmass forms over the Atlantic Ocean.It moves across the ocean toward the coast of Nigeria carrying moist air.This moisture-laden wind is responsible for the rainy season in Nigeria.The Tropical continental airmass, however, originates from the Sahara Desert and brings dry air.Equatorial Easterlies and land/sea breezes do not fit the description of the wind from the Atlantic Ocean.Answer:D. Tropical maritime airmass