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
T sign is seen in 
Select and explain. 
A. Genito urinary TB, B. PCOD, C. Spina bifida, D. Membrane in twin pregnancy
D: Membrane in twin pregnancy
Answer: D: Membrane in twin pregnancy 
Explanation: T sign - membrane in a monochoronic twin pregnancy.