A 32-year-old woman with repeat urinary tract infections presented to the office with painful urination. Suspecting another UTI, the physician sent a urine sample to the lab to identify the bacteria causing the infection. The physician's office billed for the laboratory service themselves, even though they sent the sample to an outside lab for the test. What modifier is appropriate in this case?
A. Modifier -99
B. Modifier -90
C. Modifier -52
D. No modifier would be necessary