A Patient Receives a Single Dose of Antibiotics Following a Prostate

A patient receives a single dose of antibiotics following a prostate needle biopsy. He takes 500 mg of ciprofloxacin immediately after completion of the procedure. The half-life of the medication is 8 h. At approximately how many halflives will it take for 90% of the drug to be excreted from the body?

A) 1.0
B) 2.0
C) 3.0
D) 3.3
E) 5