Solve the Problem $C ( x ) = 54 + 30 x - x ^ { 2 }$

Multiple Choice

Solve the problem.
-The cost of manufacturing clocks is given by $C ( x ) = 54 + 30 x - x ^ { 2 }$ . Also, it is known that in $t$ hours the number of clocks that can be produced is given by $x = 5 \mathrm { t }$ , where $1 \leq t \leq 12$ . Express $\mathrm { C }$ as a function of $\mathrm { t }$ .

A) $C ( t ) = 54 + 150 t - 25 t$
B) $C ( t ) = 54 + 30 t - 5$
C) $C ( t ) = 54 + 30 t + t ^ { 2 }$
D) $C ( t ) = 54 + 150 t - 25 t ^ { 2 }$