This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Physiology
Pacemaker cells are absent in 
Select and explain. 
A. Colon, B. Esophagus, C. Stomach, D. Small intestine
B: Esophagus
Answer: B: Esophagus 
Explanation: Pacemaker cells are absent in esophagus and proximal part of atomach.