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: Gynaecology & Obstetrics
Absolute contraindication for Transvaginal sonography 
Select and explain. 
A. Placenta previa, B. Imperforate hymen, C. Abruptio placenta, D. Abnormal uterine bleeding
B: Imperforate hymen
Answer: B: Imperforate hymen 
Explanation: Imperforate hymen and patient refusal are the only absolute contraindications for Transvaginal sonography.