Why is the marginal cost of capital the relevant concept for evaluating investment projects, rather than a

Question:

Why is the marginal the relevant concept for evaluating investment projects, rather than a firm’s actual, historic Cost Of Capital
Cost of capital refers to the opportunity cost of making a specific investment . Cost of capital (COC) is the rate of return that a firm must earn on its project investments to maintain its market value and attract funds. COC is the required rate of...