(3) Given that the distance between places $A$ and $B$ is 150 kilometers, a person drives a car at a speed of 60 kilometers per hour from $A$ to $B$, stays in $B$ for 1 hour, and then returns to $A$ at a speed of 50 kilometers per hour. The distance $s$ (kilometers) the car is away from $A$ can be expressed as a function of time $t$ (hours) as ( ).
(A) $s=60 t$
(B) $s=60 t+50 t$
(C) $s=\left\{\begin{array}{cl}60 t, & 0 \leqslant t \leqslant 2.5, \\ 150-50 t, & t>3.5\end{array}\right.$
(D) $s=\left\{\begin{array}{cl}60 t, & 0 \leqslant t \leqslant 2.5, \\ 150, & 2.5<t \leqslant 3.5, \\ 325-50 t, & 3.5<t \leqslant 6.5\end{array}\right.$
(3) D