An individual was given multiple doses of CSA over a 60-hour period. The CSA blood concentration was monitored continuously. A graph of CSA concentration versus time was obtained. 300 250 200 150 100 50 0 0 12 m 24 Time (h) 36 48 Suppose a particular drug has a half life of four hours. The drug is administered and reaches a peak concentration. The elimination phase then begins at zero hours: time=0 hours. At which point will the drug no longer be detectable in the bloodstream? O a. Sixteen hours after the beginning of the elimination phase: t = 16 hours Ob. Nine hours after the beginning of the elimination phase: t- 9 hours Oc. Fourteen hours after the beginning of the elimination phase: t = 14 hours 60 O d. Four hours after the beginning of the elimination phase: t=4 hours