An 18yo female college freshman, Bailey, presents to college health with an 8hr hx of abdominal pain that began in the periumbilical area and then localized to the RLQ. She has been on OCPs for teh past 6mo. Bailey denies a medical hx of UTIs, pregnancy, STDs, or chronic illness. Upon her physical exam, she is guarding on the RLQ with generalized tenderness and no masses. Her temp is 99.6 and her vitals are normal.
Based on this H&P, which of the following is the most likely diagnosis for Bailey?
a. Mittelschmerz
b. Ectopic pregnancy
c. Appendicitis
d. Gastroenteritis