uk-drcog MCQ (SBA): Ruptured Functional Ovarian Cyst

A 42-year-old woman presents to the GP with sudden onset of right iliac fossa pain during intercourse. She is not pregnant (confirmed by negative test). On examination, she has right iliac fossa tenderness and mild guarding. A pelvic ultrasound shows a 3 cm simple right ovarian cyst with a small amount of free fluid in the pouch of Douglas. What is the most likely diagnosis?