Concept:Rubber farming thrives in Nigeria's southern rainforest states.Explanation:Delta State is the largest rubber producer in Nigeria.The first rubber plantation in Nigeria was established in Sapele, Delta State, during the colonial era.This gave Delta State a strong advantage in rubber cultivation.It produces at least 70% of Nigeria's total rubber output.Ogun, Ondo, and Cross River also produce rubber, but in much smaller amounts.Answer:A. Delta State