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
Which one of the following is the primary site of production of gastrin 
Select and explain. 
A. Pylorus, B. Antrum, C. Pancreas, D. Small intestine
B: Antrum
Answer: B: Antrum 
Explanation: Gastrin secreted by
-        G cells in the antral and duodenal mucosa.
-        TG cells in stomach and ileum
-        Pituitary, brain and nerves
-        Pancreatic islets in the fetus