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.
-An explosion causes debris to rise vertically with an initial velocity of 112 feet per second. The function $s ( t ) = - 16 t ^ { 2 } + 112 t$ describes the height of the debris above the ground, $s ( t )$ , in feet, $t$ seconds after the explosion. What is the instantaneous speed of the debris when it hits the ground?

A) 224
B) $- 224$
C) $- 112$
D) 112