This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Small & Large Intestine, Subject name: Surgery
The best investigation for colorectal carcinoma: 
Select and explain. 
A. Exfoliative cytology, B. Air contrast barium enema, C. Ultrasound, D. Colonoscopy and biopsy
D: Colonoscopy and biopsy
Answer: D: Colonoscopy and biopsy 
Explanation: Ans: d (Colonoscopy and biopsy)Ref: Bailey & Love, 24,hed, p. 1179 & 23rd ed,p.1051