Concept:Southern Guinea Savanna is a transitional vegetation zone found in parts of central Nigeria.Explanation:This zone lies between the rainforest and the drier northern savannas.It is well developed in the middle-belt states.From the options provided, Kogi and Kwara are the states commonly associated with this vegetation belt.Other states in the far north, like Borno, Sokoto, Kano or Niger, are too dry, while Cross River is mostly rainforest.Answer:B. Kogi and Kwara