A 50-Year-Old Man Complains to His Primary Care Physician About

A 50-year-old man complains to his primary care physician about a chronic burning sensation in his chest.The pain is worse when he lies down at night after a large meal,and it can be alleviated to some degree by the use of over-the-counter antacids.The pain experienced by the patient is probably caused by dysfunction of which of the following gastrointestinal structures?

A) Lower esophageal sphincter
B) Pylorus
C) Salivary glands
D) Pancreas
E) Gallbladder