The pattern we use with air resistance works on objects that are traveling on level ground, too. For example, if you stop pedaling your bicycle and just coast on a straight, level road, eventually you'll coast to a stop. The resistance here is proportional to your velocity, just like it is for a falling body.
The general differential equation for coasting to a stop is (dv/dt ) = -kv
where k is a constant. What's the terminal velocity in this case?
a. 0
b. v
c. k
d. –k
e. - ∞
dv/dt = -kv
dv/v = -k dt
ln v = -kt
v = e^(-kt)
Terminal velocity happens as t→∞, so it is zero (assuming k>0, which should have been stated)
But then, we already knew that, right? The bicycle doesn't keep on rolling forever.