The correct answer is C. This patient has pelvic inflammatory disease (PID), an acute infection of the upper genital tract in women, most commonly caused by C. trachomatis and N. gonorrhoeae. Early diagnosis and treatment can prevent long-term sequelae such as ectopic pregnancy or infertility. In the diagnostic process, it is important to rule out pregnancy with a urine beta human chorionic gonadotropin (β-hCG) test. Although PID is rare in pregnancy, it can occur within the first 12 weeks of gestation. Pregnancy will alter the treatment protocol from outpatient to inpatient treatment. Further, this patient's partner should be examined and treated as needed.

Administration of ceftriaxone IM and a prescription for doxycycline for 14 days (choice A) is the appropriate outpatient treatment for PID once pregnancy has been excluded.

Asking the patient to return the next day for results from the nucleic acid amplification test (NAAT) (choice B) is inappropriate without prescribing treatment. Another issue to consider is the increase in Neisseria gonorrhoeae resistance to cephalosporins. One drawback to NAAT is that it does not determine antimicrobial sensitivity. Sending the sample for culture (which takes longer to get results) allows for the determination of antibiotic sensitivity which would be helpful if the patient does not improve on empiric treatment.

Prescribing levofloxacin and metronidazole for 14 days (choice D) is the outpatient regimen for patients with PID and severe penicillin allergy (e.g. anaphylaxis or Stevens-Johnson syndrome). This patient's penicillin allergy doesn't sound severe, but if there is sufficient concern, a test dose procedure can be followed for cephalosporin use. An additional concern is that levofloxacin is contraindicated in pregnancy. The most appropriate next step remains testing the urine for β-hCG.

Although laparoscopy (choice E) is the most accurate test for PID, it is rarely necessary and will likely delay treatment. Laparoscopy is indicated when the diagnosis is unclear or when treatment has failed.