This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Physiology
Cholecystokinin is produced from: 
Select and explain. 
A. Hepatocyte, B. Gastric mucosa, C. Duodenal mucosa, D. Epithelial cells of distal common bile duct
C: Duodenal mucosa
Answer: C: Duodenal mucosa 
Explanation: The major factor controlling the contraction of the gallbladder is the hormone cholecystokinin (CCK), which is released from the duodenal mucosa (I cells) in response to the ingestion of fats and amino acids. REF: GUYTON 12TH ED.