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: Radiology
The "Target sign" ultrasonographically means: 
Select and explain. 
A. Ovarian carcinoma, B. Ectopic kidney, C. Intussusception, D. Liver metastasis
C: Intussusception
Answer: C: Intussusception 
Explanation: Ans. Intussusception