Solve the Problem $C ( x )$ , and the Revenue Function

Multiple Choice

Solve the problem.
-Given the cost function, $C ( x )$ , and the revenue function, $R ( x )$ , find the number of units $x$ that must be sold to brea
$$\begin{array} { l } C ( x ) = 56 x + 900 \\R ( x ) = 71 x\end{array}$$

A) 62 units
B) 60 units
C) 61 units
D) 11 units en.