Inputs are traded in the factor market.

In the short run, marginal product of labor increases at first and then falls because

A) managerial inefficiency sets in when a firm gets too large. B) the new workers do not have as much experience as those who have been with the firm for a long time and therefore are not as productive. C) there are fewer opportunities for division of labor and specialization when fewer workers are hired. D) as more labor is hired, they are not as skilled as the first ones hired.

Mary decreases her consumption of Good X after the price of Good Y decreased. For Mary

A) Good X and Good Y are substitutes. B) Good X and Good Y are complements. C) Good X is an inferior good. D) Good Y is an inferior good.