This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Obstetrics and gynaecology, Subject name: Radiology
The characteristic finding in USG of ectopic pregnancy is 
Select and explain. 
A. Resistance in color doppler, B. Absence of gestational sac in uterus, C. Free fluid in peritoneal cavity, D. Complex adnexal mass
B: Absence of gestational sac in uterus
Answer: B: Absence of gestational sac in uterus 
Explanation: <img alt="" src=" />An ectopic pregnancy occurs when a feilized egg implants and grows outside the main cavity of the uterus