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. What is the instantaneous speed of the ball $0.5$ seconds after it was hit?

A) $- 28.8$
B) 96
C) $- 67.2$
D) $28.8$