Solve the Problem $16 \mathrm { ft } / \mathrm { sec }$

Solve the problem.
-If an object is thrown upward with an initial velocity of $16 \mathrm { ft } / \mathrm { sec }$ , its height after $\mathrm { t }$ sec is given by $s ( t ) = 16 t - 16 t ^ { 2 }$ . Find the maximum height attained by the object. (The object will attain maximum height exactly at the halfway point in terms of the time $t$ , where $t = 0$ is at the beginning of the object's flight, and the final time is when the object hits the ground.)

A) $16 \mathrm { ft }$
B) $4 \mathrm { ft }$
C) $- 12 \mathrm { ft }$
D) $0 \mathrm { ft }$