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: Surgery
Commonest presentation of Ca rectum is: 
Select and explain. 
A. Diarrhoea, B. Constipation, C. Bleeding P/R, D. Feeling of incomplete defaecation
C: Bleeding P/R
Answer: C: Bleeding P/R 
Explanation: Bleeding is the earliest and most common symptom. Often the bleeding is slight in amount.
Alteration in bowel habit is the next most frequent symptom. An early morning urgency may occur but he passes only mucus & blood (early morning bloody diarrhea). An annular carcinoma at pelvi-rectal jn. may lead to constipation & obstruction.

Other symptoms are -

Tenesmus - almost invariably present in tumors of lower half of rectum.
Pain - is a late symptom.
Weight loss.