The law of diminishing marginal product (or returns) states that:
as more and more of a variable input, such as labor, is employed to a short-run production process, beyond a point output will increase at an increasing rate
as more and more of a variable input, such as labor, is employed to a short-run production process, beyond a point output will increase at a decreasing rate
as more and more of a variable input, such as labor, is employed to a short-run production process, beyond a point output will decrease at a decreasing rate
as more and more of a variable input, such as labor, is employed to a short-run production process, beyond a point output will decrease at an increasing rate