The answer is (A) the object must be at rest.
When all of the forces acting on an object balance, the net force is zero and hence the object will not move.
Yes, the direction might also change under some special circumstances.
It lets the viewer know it's something to do with underwater.
'A' and 'C' both show that behavior.
'D' also shows it, but the object is moving backwards when time begins.
First it moves faster and faster backwards, then it moves slower and slower backwards.
False.
Theories are hypotheses that have been shown to accurately and predictably explain results obtained through repeated experimentation, to the point where the hypothesis can be assumed to be true. Then, such a hypothesis would be considered a theory.