Which of the Following Conditions Must Hold to Ensure That

Multiple Choice

Which of the following conditions must hold to ensure that profits are,in fact,at a maximum?

A) d(MC(Q) ) /dQ > 0
B) d(MC(Q) ) /dQ < 0
C) d²(Q) /dQ² < 0
D) d(MC(Q) ) /dQ > 0 and d²(Q) /dQ² < 0