The concentration, in milligrams per liter (mg/L), of a certain drug in a patient's bloodstream hours after it is administered can be modeled by the function . Based on the model, which of the following statements best interprets the equation ?
One hour after administration, the drug concentration in the bloodstream is 4 mg/L.
The drug concentration reaches its peak of 4 mg/L after 1 hour.
It takes 4 hours for the drug concentration to reach 1 mg/L.
The drug concentration decreases by 4 mg/L after 1 hour.
