How proffersor Lionel robbins explains opportunity cost?

Professor Lionel Robbins explains opportunity cost as the value of the next best alternative that is forgone when making a decision. He emphasizes that every choice involves trade-offs, where selecting one option means sacrificing the benefits that could have been gained from the alternatives. This concept underlines the importance of considering not just the costs of a decision, but also what is lost by not choosing the next best alternative. Thus, opportunity cost is a fundamental principle in economics, reflecting the scarcity of resources and the need for efficient allocation.