The Keynesian AS-Curve Differs from the Classical AS-Curve, Since Keynes

The Keynesian AS-curve differs from the classical AS-curve, since Keynes

A) thought that labor markets worked smoothly to always establish full employment
B) thought that nominal wages were rigid even when there was unemployment
C) thought that nominal wages were flexible even when there was unemployment
D) described the AS-curve as completely vertical
E) assumed that firms tried to exploit the work force by paying them substandard wages