During a Normal Swallowing Sequences ,The Smooth Muscle Which Surrounds

Multiple Choice

During a normal Swallowing sequences ,the smooth muscle which surrounds the gastro esophageal junction.

A) Remains tonically constricted until the bolus arrives at this junction.
B) Relaxes even before the oncoming peristaltic wave has arrived.
C) constricts further on the passing bolus and allows a gradual esophageal emptying.
D) Is never constrict at all , and has no participation of any kind in the Swallowing process.