Choose the One Alternative That Best Completes the Statement or Answers

Multiple Choice

Choose the one alternative that best completes the statement or answers the question.
-The concentration $\mathrm { C }$ (arbitrary units) of a certain drug in a patient's bloodstream can be modeled using $C ( t ) = \frac { t } { ( 0.423 t + 2.366 ) ^ { 2 } }$ , where $t$ is the number of hours since a 500 milligram oral dose was administered. Using the TABLE feature of a graphing utility, find the time at which the concentration of the drug is greatest. Round to the nearest tenth of an hour.

A) $5.6$ hours
B) $6.4$ hours
C) $7.1$ hours
D) $7.9$ hours