The Height $h ( x )$ , of a Punted Rugby Ball Is Given By

Multiple Choice

The height, $h ( x )$ , of a punted rugby ball is given by
$h ( x ) = \frac { 1 } { 64 } x ^ { 2 } + \frac { 13 } { 32 } x + 2$
where x is the horizontal distance in feet from the point where the ball is punted. How far, horizon- tally, is the ball from the kicker when it is at its highest point?

A) 28 feet
B) 13 feet
C) 18 feet
D) 23 feet
E) 16 feet