For the Short-Run Cost Function AVC = a + BQ $U$

Multiple Choice

For the short-run cost function AVC = a + bQ + cQ²,

A) the AVC curve is $U$ -shaped when a < 0,b > 0,and c < 0.
B) the AVC curve is $U$ -shaped when a > 0,b < 0,and c > 0.
C) the corresponding SMC function is $S M C = a Q + 2 b Q ^ { 2 } + 3 c Q ^ { 3 }$ .
D) both a and c
E) all of the above