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: Medicine
Chemo prevention trials shown effective in reducing of –  a) Lymphoma  b) Breast Ca  c) Pancreatic Ca  d) Ca urinary bladder  e) Aero digestive tract 
Select and explain. 
A. ab, B. be, C. ace, D. acd
B: be
Answer: B: be 
Explanation: None