This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Gastrointestinal System, Subject name: Physiology
Highest frequency of BER is seen in which of the following? 
Select and explain. 
A. Stomach, B. Duodenum, C. Jejunum, D. Ileum
B: Duodenum
Answer: B: Duodenum 
Explanation: BER - Basal electrical rhythm is the frequency of the electrical activity (slow waves) in the digestive tract. Stomach = 3-4/min., Duodenum = 12/min, jejunum = 9/min, ileum = 7/min.