-The Maximum Units of Input You Would Possibly Hire Would

$$\begin{array}{l}\begin{array} {ccc } \text { Units of Input}&\text { Units of Output }\\1 & 4 \\2 & 9 \\3 & 13 \\4 & 15 \\5 & 16 \\6 & 16 \\7 & 15\end{array}\end{array}$$
-The maximum units of input you would possibly hire would be

A) 3.
B) 4.
C) 5.
D) 6.
E) 7.