Solve the Problem $C ( x )$ (In Dollars) to Produce $x$

Multiple Choice

Solve the problem.
-If the average cost per unit $C ( x )$ (in dollars) to produce $x$ units of plywood is given by $C ( x ) = \frac { 1200 } { x + 40 }$ , what is the unit cost for 40 units?

A) $\$ 15.00$
B) $\$ 0.75$
C) $- \$ 10.00$
D) $\$ 30.00$