What is the length of the lower esophageal sphincter?

Ans. is 'b' i.e., 3-5 cm [Ref: McGraw-Hill Concise Dictionary of Modem Medicine. 2002 by The McGraw-Hill Companies, Inc.)* Lower esophageal sphincter is a zone of 3-5 cm located at the junction of the distal esophagus and gastric cardia acting as a physical barrier in preventing gastric reflux.