This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Unknown
When a horseshoe kidney develops, the ascent of the kidney is restricted by the: 
Select and explain. 
A. Internal iliac artery, B. External iliac artery, C. Common iliac artery, D. Inferior mesenteric artery
D: Inferior mesenteric artery
Answer: D: Inferior mesenteric artery 
Explanation: A horseshoe kidney develops when the inferior poles of the two kidneys fuse together as they ascend into the abdomen from the pelvis. The first anterior mid­line vessel that is encountered by the horseshoe kidney is the inferior mesenteric artery. This artery prevents the kidney from continuing its ascent.