Inter industry competition refers to the fact that:

A. Monopolistic producers establish a common price for their products
B. Products are identical in a purely competitive industry
C. Firms which sell a product at one stage of production buy materials and parts from other firms at prior stages of production
D. In some markets the producers of a certain commodity might face competition from products of other industries

D. In some markets the producers of a certain commodity might face competition from products of other industries