A 20-Year-Old Female Client Comes to the Clinic Due to Abdominal

A 20-year-old female client comes to the clinic due to abdominal cramping. She informs the nurse midwife that it is more than a month and a half past the date of her expected menstrual period. The client's human chorionic gonotropin level is 5,500 mIU/mL. Pregnancy is suspected. Which diagnostic test should the nurse midwife order to obtain the most accurate diagnosis of pregnancy at this time?

A) Transabdominal ultrasound
B) Transvaginal ultrasound
C) Serum progesterone
D) Serum estrogen