Concept:Economic rent is the extra payment received above the opportunity cost of supplying a factor of production.Explanation:John's current weekly earnings are ₦150.His opportunity cost is the ₦30 weekly wage he gave up as an apprentice engineer.The surplus above the opportunity cost is ₦150−₦30=₦120.This surplus payment, made because of his unique skill as a trumpet player, is economic rent.Answer:D. economic rent