Whenever the net force on a moving object is zero its acceleration is

We only need to look at Newton's 2nd law of motion:

Net force = (mass) x (acceleration)

If the net force on an object is zero, then either its mass or its acceleration must be zero.  If it's called an "object", then its mass isn't zero, so its acceleration is zero.

im srry but ur wrong the answer is d a smooth rock, some red dirt, and an empty bird's nest.