The Relationship Between the Marginal Product of Capital (MP_K),the Product $\times$

The relationship between the marginal product of capital (MP_K) ,the product price (P) ,and marginal revenue product of capital (MRP_K) in a perfectly competitive market is

A) MP_K = P $\times$ MRP_K
B) MP_K = P + MRP_K
C) MRP_K = P/MP_K
D) MRP_K = P $\times$ MP_K
E) MRP_K = P + MP_K