Solve the Problem $c ( x ) = 3 x ^ { 2 } - 204 x + 46$

Multiple Choice

Solve the problem.
-Bob owns a watch repair shop. He has found that the cost of operating his shop is given by $c ( x ) = 3 x ^ { 2 } - 204 x + 46$ , where $c$ is cost and $x$ is the number of watches repaired. How many watches must he repair to have the lowest cost?

A) 46 watches
B) 34 watches
C) 30 watches
D) 23 watches