During the Contractions of Gastric Emptying

During the contractions of gastric emptying

A) the stomach is induced to contract by increased sympathetic activity.
B) the pyloric sphincter opens to allow stomach contents to pass quickly and completely into the duodenum.
C) the pyloric sphincter closes to allow only a small amount of liquefied chyme to pass into the duodenum with each contraction of the stomach.
D) the strength of stomach wall contractions is increased when the duodenum secretes cholecystokinin.
E) the strongest contractions are in the antrum of the stomach because the intrinsic pacemaker frequency is fastest there.