Solve the Problem $C ( t )$ , in Milligrams After $t$

Solve the problem.
-A drug is injected into a patient and the concentration of the drug is monitored. The drug's concentration, $C ( t )$ , in milligrams after $t$ hours is modeled by $C ( t ) = \frac { 6 t } { 3 t ^ { 2 } + 2 }$ . Estimate the drug's concentration after 4 hours. (Round to the nearest hundredth.)

A) $0.48 \mathrm { mg }$
B) $1.71 \mathrm { mg }$
C) $0.35 \mathrm { mg }$
D) $1.58 \mathrm { mg }$