help please. thank you

If the firm is producing at a quantity of output where marginal cost exceeds marginal revenue, then ________.

select all that apply.

A. the firm's perceived demand will shift to the left

B. the firm should reduce production

C. each marginal unit adds profit by bringing in more revenue than its cost

D. the excess profit would attract additional competition

Total Cost can be expressed as:

Select all that apply

A. (average fixed cost + average variable cost)

B. (average cost x quantity)

C. (implicit cost + explicit cost)

D. (price x quantity)