Consider these statements written in ordinary language:
A The speed of the car is proportional to the distance it has traveled.
B The car is speeding up.
C The car is slowing down.
D The car always travels the same distance in the same time interval.
E We are driving backwards.
F Our acceleration is decreasing. Denoting by $s(t)$ the distance covered by the car at time $t$, and letting $k$ denote a constant, match these statements with the following mathematical statements by entering the letters A through F on the appropriate boxes:
$s'' < 0 .$
$s'$ is constant
$s' < 0$
$s''' < 0$
$s'' > 0$
$s'=ks$