One of the advantages of acrylic paint is that it can be cleaned up using this liquid.

The correct answer is WATER.

One of the advantages of acrylic paint is that it can be cleaned up using water.

Explanation:

Mostly, one of the advantages of using acrylic paint, aside from the fact that it drys fast, is that it can be removed with just water and soap. The effectiveness of this depends on the surface where it is being use, and if the acrylic paint is still wet or has dried up.

If the paint has dried up it may take a bit of scrubbing and extra work, but most of the times water and soap is just good enough.  If not some alcohol or nail polish remover can help.

You can easily remove acrylic paint with water and soap on a non abrasive surface, actually if it is a plane surface like plastic, with no texture for the paint to be able to attach to,  you  will be able to remove it with your fingers just scrubbing it away.

If you were to remove it from clothing it  may be a bit harder as the paint adheres more to the texture of the surface.

From personal experience if the acrylic paint hasn't dry yet, it can simply be removed with warm water and soap.

Most of the paints can be clean up with the same medium that was used to dilute them in the first place.  Acrylic paint dilutes with water.

As mentioned before one of the advantages of using acrylic paint is that it dries fast, so the faster you try to remove it the better result you will get.

triumphantly i think that is the answer.