Final answer:
Colon cancer can be visualized during a colonoscopy, a procedure that allows a doctor to examine the lining of the large intestine and detect any suspicious areas or polyps.
Step-by-step explanation:
The correct answer is b. colonoscopy. Colon cancer can be visualized during a colonoscopy, which is a procedure that uses a long tube with a camera to examine the lining of the large intestine. During a colonoscopy, a doctor can identify any suspicious areas that may be cancerous and also remove any growths called polyps, which can develop into cancerous lesions. This procedure is considered the gold standard for diagnosing colorectal cancer.