'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.
The radius of the cylinder is equal to half the diameter:

The volume of the cylinder is given by:

where h is the heigth of the cylinder. Converting into meters,

And the density of the material will be given by the ratio between the mass and the volume:

F=ma therefore 25kg*1.0m/s^2=25N force on the mass