What Does the Law of Diminishing Marginal Returns State

What does the law of diminishing marginal returns state?

A) When all inputs to production are increased in equal proportions, output will eventually decrease.
B) When one input is increased, with all other inputs unchanged, the marginal product of the input will eventually decline.
C) When one input is held constant, and all other inputs are increased, output will eventually decrease.
D) When one input is increased, and all other inputs are held constant, output will increase at an increasing rate.
E) When all inputs to production are increased in equal proportions, the addition to output will increase at an increasing rate.