A doctor prescribes levofloxacin to a patient who is suffering various symptoms of prostatitis. These symptoms are caused by inflammation of the prostate resulting from a bacterial infection. Levofloxacin is an effective drug for treating prostatitis because
a. it is an antibiotic.
b. it is a vasodilator.
c. it is a PDE5 inhibitor.
d. it is an androgen agonist.