This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Obstetrical Ultrasonography in the First Trimester, Subject name: Radiology
T sign is seen in - 
Select and explain. 
A. Genital TB, B. Membrane in twin pregnancy, C. Molar pregnancy, D. Choriocarcinoma
B: Membrane in twin pregnancy
Answer: B: Membrane in twin pregnancy 
Explanation: Ans. is 'b' i.e., Membrane in twin pregnancyo 'T sign' refers to appearance of the inter-twin membrane in a monochorionic twin pregnancy.