A 9-week pregnant woman presents with mild vaginal bleeding and lower abdominal cramping. She has no shoulder tip pain or syncope. On examination, cervix is closed and she is haemodynamically stable. What is the most appropriate next investigation?ASerum CA-125 levelBTransvaginal ultrasound to assess location and viability of the pregnancyCAbdominal X-rayDImmediate diagnostic laparoscopyENo investigation is needed; reassure and dischargeCheck my answer