This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Intestinal obstruction, Subject name: Surgery
Coffee bean sign is usually seen in: 
Select and explain. 
A. Volvulus, B. Pyloric obstruction, C. Intussusception, D. Intestinal obstruction
A: Volvulus
Answer: A: Volvulus 
Explanation: Coffee bean sign is usually seen in Sigmoid Volvulus.