<s>[INST] context: The posterior superior pancreaticoduodenal artery arises from the gastroduodenal artery and travels behind the first part of the duodenum, supplying the proximal portion, with branches to the head of the pancreas. Duodenal ulcers commonly arise within the first portion of the duodenum, thus making the posterior superior pancreaticoduodenal artery one of the more frequently injured vessels. The superior mesenteric artery supplies derivatives of the midgut from the distal half of the duodenum to the left colic flexure. It lies inferior to the region of ulceration. The inferior pancreaticoduodenal artery arises from the superior mesenteric artery and supplies the distal portion of the second part of the duodenum, with anastomoses with its superior counterparts. The inferior mesenteric artery is responsible for supplying most of the hindgut derivatives, generally supplying intestine from the left colic flexure to the superior aspect of the rectum. The right gastric artery is responsible for supplying the pyloric portion of the lesser curvature of the stomach. [/INST] question: Radiographic examination of a 42-year-old female reveals penetration of the duodenal bulb by an ulcer, resulting in profuse intraabdominal bleeding. Which of the following arteries is the most likely source of the bleeding? | options: A: Posterior superior pancreaticoduodenal B: Superior mesenteric C: Inferior mesenteric D: Inferior pancreaticoduodenal | answer: A </s>