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
An 8 week pregnant female presented with vaginal bleeding and ruptured cysts of hydatidiform mole. In case of hydatidiform mole, the investigation used for diagnosis is: 
Select and explain. 
A. HCG titer, B. USG, C. Chest X-ray, D. All of the above
B: USG
Answer: B: USG 
Explanation: Though beta-hCG levels are helpful, the diagnosis of molar pregnancy is more frequently found sonographically because of the identifiable diffuse swelling and enlargement of the chorionic villi. Most first-trimester complete moles demonstrate a typical sonographic appearance: a complex, echogenic, intrauterine mass containing many small cystic spaces. Fetal tissues and amnionic sac are absent. In contrast, sonographic features of a paial molar pregnancy include a thickened, hydropic placenta with a concomitant fetus. Ref: Hoffman B.L., Schorge J.O., Schaffer J.I., Halvorson L.M., Bradshaw K.D., Cunningham F.G., Calver L.E. (2012). Chapter 37. Gestational Trophoblastic Disease. In B.L. Hoffman, J.O. Schorge, J.I. Schaffer, L.M. Halvorson, K.D. Bradshaw, F.G. Cunningham, L.E. Calver (Eds), Williams Gynecology, 2e.