Which of the following is assessed during a gastroscopy?

A gastroscopy, also known as esophagogastroduodenoscopy (EGD), is a procedure that allows a healthcare provider to examine the upper part of the gastrointestinal tract. This includes the esophagus, stomach, and the first part of the small intestine (duodenum). The technique utilizes a flexible tube with a camera that provides real-time visual assessment, allowing for the diagnosis of various conditions such as inflammation, ulcers, tumors, and other anomalies in this region.

The upper gastrointestinal tract conditions that can be assessed during a gastroscopy include issues such as gastroesophageal reflux disease (GERD), peptic ulcers, esophagitis, and cancers of the esophagus or stomach. This procedure is specifically designed to visualize these upper structures, making it the appropriate choice when investigating problems in this area.

Other options pertain to areas outside the scope of a gastroscopy. For instance, assessing lower colon conditions typically involves a different procedure, such as a colonoscopy. Gallbladder function is evaluated through imaging studies like ultrasounds or HIDA scans, while rectal health would be examined through procedures focused on the lower GI tract. Thus, option B is the correct answer as it directly relates to the purpose and capabilities of a gastroscopy.