Which type of scope is used to examine the rectum and sigmoid colon?

The correct answer is a sigmoidoscope, which is specifically designed for examining the rectum and sigmoid colon. This instrument allows healthcare professionals to visualize and assess conditions in this particular area of the lower gastrointestinal tract. The sigmoidoscope can assist in diagnosing issues such as hemorrhoids, polyps, and inflammation, and it also enables interventions like biopsy or treatment of abnormalities within the rectum and sigmoid colon.

A colonoscope is also used for examining the colon but has a longer reach, allowing access to the entire colon rather than just the rectum and sigmoid section. A gastroscope is intended for examining the upper gastrointestinal tract, including the esophagus, stomach, and duodenum, which makes it irrelevant for examining the lower gastrointestinal regions. A bronchoscope is used for inspecting the airways and lungs, which is unrelated to the gastrointestinal system. Therefore, the sigmoidoscope is the most appropriate choice for exploring the rectum and sigmoid colon.