Choose the One Alternative That Best Completes the Statement or Answers

Multiple Choice

Choose the one alternative that best completes the statement or answers the question.
Solve the problem.
-A foul tip of a baseball is hit straight upward from a height of 4 feet with an initial velocity of 112 feet per second. The function $s ( t ) = - 16 t ^ { 2 } + 112 t + 4$ describes the ball's height above the ground, s(t) , in feet, $t$ seconds after it was hit. The ball reaches its maximum height above the ground when the instantaneous speed reaches zero. After how many seconds does the ball reach its maximum height?

A) 112
B) $\frac { 3 } { 32 }$
C) $\frac { 7 } { 2 }$
D) 7