This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: G.I.T, Subject name: Medicine
The most likely cause of fluctuating jaundice in a middle-aged or elderly man is - 
Select and explain. 
A. Periampullary carcinoma, B. Liver fluke infestation, C. Choledochal cyst, D. Carcinoma hed of pancreas
A: Periampullary carcinoma
Answer: A: Periampullary carcinoma 
Explanation: Periampullary cancer is a cancer that forms near the ampulla of Vater, an enlargement of the ducts from the liver and pancreas where they join and enter the small intestine.It consists of: . ampullary tumour from ampulla of Vater 2. cancer of lower common bile duct 3. duodenal cancer adjacent to ampulla 4. carcinoma head of pancreas It presents with painless jaundice which may have waxing and waning nature because at times the sloughing of the tumor tissue relieves the obstruction paially. Ref Davidson edition23rd pg802