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: Surgery
Based on Epidemiological studies, which of the following has been found to be most protective against carcinoma colon 
Select and explain. 
A. High fiber diet, B. Low fat diet, C. Low selenium diet, D. Low protein diet
A: High fiber diet
Answer: A: High fiber diet 
Explanation: dietary factos involved in development of carcinoma colon are .- Red meat and saturated fat increases the incidence of colonic cancer. - Cholesterol increases the bile acid concentration in the intestinal lumen which acts as cocarcinogen. - High fibre diet protects the colon against cancer. - Calcium in diet prevents colonic cancer by combining with bile salts and reducing bile salt concentration in the colon. It directly acts on the colonic mucosal cells to reduce their proliferative potential. - Diet with lack of fibre increases the risk. Diet with high fat increases the risk. ref:SRB&;s manual of surgery,ed 3,pg no 834