5. (8%) Suppose Taiwan's rice market is perfectly competitive. A typical farmer's short-run total cost function is
$TC = 0.1q^3 + 10q^2 + 400q + 520,$
where 520 is the sunk cost. Since Taiwan's fertile lands are limited, new farmers entering the rice market have to cultivate on infertile lands, increasing the total cost of a typical farmer. Assume that there is no technological progress of rice production in the long run. Which of the following statements is (are) correct?
(A) The average fixed cost curve is strictly decreasing as \( q \) increases.
(B) The average variable cost curve is strictly decreasing as \( q \) increases.
(C) If a typical farmer cultivates, the marginal cost curve is strictly increasing as \( q \) increases.
(D) In the short run, the shutdown price for a typical firm is 50.
(E) The long-run supply curve for Taiwan's rice market is upward sloping.
統計: 尚無統計資料