Which of the Following Is a Common Mistake Managers Make

Which of the following is a common mistake managers make?

A) Using marginal analysis to make output decisions.
B) Maximizing the value of the firm instead of maximizing the firm's profits.
C) Reducing price to increase the firm's share of total market sales.
D) Treating implicit opportunity costs as part of the total costs of using resources.
E) all of the above.