This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Ovarian Tumors and Vulvar cancer, Subject name: Gynaecology & Obstetrics
A 30 yrs old female, presents to the emergency with complaint of sudden severe abdominal pain; an abdominal mass is palpable on examination; Most likely diagnosis is: 
Select and explain. 
A. Torsion of subserous fibroid, B. Twisted ovarian cyst, C. Rupture of ectopic preg, D. Rupture of ovarian cyst
B: Twisted ovarian cyst
Answer: B: Twisted ovarian cyst 
Explanation: The history of sudden onset of pain abdomen points towards a Torsion Present as a palpable mass because torsion occurs mostly in cysts which are more than 8 to 10 cms size. MC tumour to show torsion: Dermoids C/f : Acute abdominal Pain, Fever, Vomiting Rx Surgical Emergency Requiring Urgent Laparotomy Detorsion of ovary and Ovariopexy after removal of tumour should be attempted