The Path of Flight (Trajectory) of a Football Thrown by a Quarterback

Multiple Choice

The path of flight (trajectory) of a football thrown by a quarterback is described by the following function: $y ( x ) = - 0.002 x ^ { 2 } + 0.7 x + 7$ where $y =$ vertical position of football relative to the ground (ft)
$x =$ horizontal position of football relative to launch position ( $\mathrm { ft } )$ How high above the ground is the football when it is 30 yards downfield from the quarterback?

A) 26.2 ft
B) 29.8 ft
C) 13.8 ft
D) 53.8 ft