This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Small & Large Intestine, Subject name: Surgery
A 58 year old male presents with fatigue, abdominal pain and bloody stools. Colonoscopy reveals a mass in the descending colon. For surgical removal of the mass, ligation of which of the following arteries is required? 
Select and explain. 
A. Superior mesenteric artery, B. Inferior mesenteric artery, C. External iliac artery, D. Internal iliac artery
B: Inferior mesenteric artery
Answer: B: Inferior mesenteric artery 
Explanation: Answer: b) Inferior mesenteric artery (SABISTON 19th ED, P-1299; SCHWARTZ 10TH ED, P-1187)Left Colectomy.For lesions or disease states confined to the distal transverse colon, splenic flexure, or descending colon, a left colectomy is performed.The left branches of the middle colic vessels, the left colic vessels, and the first branches of the sigmoid vessels are ligated.A colocolonic anastomosis can usually be performed.