Penny is diagnosed with retrovirus. Report this with code:

A) B97.3.
B) B97.30.
C) B97.31.
D) B99.9.

B97.30 is the correct code for retrovirus, unspecified. Option B is the only code that specifically addresses retrovirus, while option A (B97.3) is a non-specific code for viral agents as the cause of diseases classified elsewhere. Option C (B97.31) is for SARS-associated coronavirus, and option D (B99.9) is for unspecified infectious disease.