Which of the Following Statements Is (Are) TRUE

Multiple Choice

Which of the following statements is (are) TRUE?
I. As market prices increase, industry output rises because individual firms have upward-sloping marginal cost curves.
II. As market prices increase, industry output rises because high-cost producers enter the industry.
III. As market prices increase, industry output rises because individual firms have upward-sloping short-run supply curves.

A) I, II, and III
B) II and III
C) III
D) II