Concept:An emerging agricultural export crop is one that is newly becoming commercially important for international trade, especially as Nigeria diversifies away from oil.
Explanation:Cassava is one of Nigeria's most widely cultivated crops, and it has gained attention as an emerging export because it can be processed into cassava flour, starch, ethanol, and other products.
Government agricultural policies have promoted cassava and its derivatives for foreign exchange earnings.
Cocoa, cotton, and palm products are considered traditional export crops, not emerging ones.
Cocoa, in particular, has been a leading cash crop for many decades in Nigeria.
Therefore, among the given options, cassava best fits the description of an emerging agricultural export crop in Nigeria.
Answer:A. cassava