Concept:The Lake Chad Basin Commission is a regional body of countries that share the Lake Chad water resources.
Explanation:The main member countries of the Commission include Cameroon, Chad, Niger, and Nigeria.
Other members include the Central African Republic, Libya, Sudan, and Algeria.
From the options given, Niger and Cameroon are both actual members of the Commission.
Benin and Mali are not members of the Commission.
Therefore, the only valid pair is Niger and Cameroon.
Answer:A. Niger and Cameroon