Concept:Climate is the major regional factor that decides which crops can grow successfully in West Africa.
Explanation:The amount and pattern of rainfall and temperature determine crop distribution.
West Africa has different climate belts, such as the forest zone, savanna, and Sahel.
These belts support different crops based on their water and heat requirements.
Soil, relief, and diseases do affect crop growth at local levels.
However, the strongest overall influence on crop distribution across the region is climate.
Answer:A. climate