The term marginal revenue product (MRP) refers to the change in output if an additional worker is employed

Why does a profit-maximizing firm hire labor up to the point where the value of marginal product equals the wage rate?

What will be an ideal response?

A pecuniary externality _____

a. affects the prices facing the third parties on which the externality falls b. affects the products bought by third parties c. affects the production functions of third parties d. affects the production functions of producers of the externalities