If Profits Depend on Both How Much Is Produced (Output)

Multiple Choice

If profits depend on both how much is produced (output) and on the level of advertising, then a profit-maximizing firm should choose the levels of output and advertising at which

A) the marginal revenue of output equals the marginal cost of output.
B) the addition to total revenue of the last unit of advertising equals the addition to total cost of the last unit of advertising.
C) total revenue equals total cost for both output and advertising.
D) both a and b
E) both b and c