An Egg-Eating Snake Carefully Retracts Its Teeth and Engulfs a Bird

An egg-eating snake carefully retracts its teeth and engulfs a bird egg whole.Once it has completely closed its mouth,it can then break the eggshell internally and let the liquid contents move down the digestive tract.To avoid having the sharp pieces of eggshell proceed to the stomach,it must regurgitate them before they pass the

A) small intestine.
B) epiglottis.
C) cardiac sphincter.
D) pyloric sphincter.
E) esophagus.