This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Tubal Pregnancy, Subject name: Gynaecology & Obstetrics
A young female with 2 month amenorrhea presents with sudden abdominal pain with adnexal mass, urine pregnancy test is positive. Most likely diagnosis: 
Select and explain. 
A. Ovarian tumor, B. Ectopic pregnancy, C. Pelvic tumor, D. Ovarian cyst
B: Ectopic pregnancy
Answer: B: Ectopic pregnancy 
Explanation: Ans. b. Ectopic pregnancy (Ref: William's Obstetrics 22/e p253, 265)