Final answer:
A lesion in the mucous membrane of the stomach or duodenum is known as a peptic ulcer, with a duodenal ulcer specifically referring to this condition in the duodenum(option c). It's often caused by Helicobacter pylori and is treated with antibiotics and acid-reducing medications.
Step-by-step explanation:
A sore or lesion of the mucous membrane in the stomach or duodenum is most appropriately identified as a peptic ulcer. Specifically, when such a lesion occurs in the duodenum, it is termed a c) duodenal ulcer.
This type of ulcer can be caused by an infection with the bacterium Helicobacter pylori, as well as by the ingestion of substances that harm the protective mucous layer of the stomach, such as certain medications including NSAIDs (Nonsteroidal anti-inflammatory drugs). Symptoms of a duodenal ulcer often include upper abdominal pain that may improve with eating, and these can also be accompanied by belching, vomiting, weight loss, and a poor appetite. Diagnosis is typically confirmed with an endoscopy, and treatment involves antibiotics to eradicate H. pylori along with medications to reduce stomach acid and promote healing.