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
Ectopic pregnancy, characteristic finding in USG is - 
Select and explain. 
A. Absence of gestational sac in uterus, B. Complex adnexal mass, C. Resistance in colored Doppler, D. Free fluid in peritoneal cavity
B: Complex adnexal mass
Answer: B: Complex adnexal mass 
Explanation: "The Presence of a non - ovarian complex adnexal mass is the most sensitive and specific USG finding for ectopic pregnancy".
—USG in radiology
"The presence of a fetal heart beat outside the uterine cavity is pathognomonic for an ectopic pregnancy".
—USG in radiology