This is a test of commonsense with single/multi-choices. Complete the next sentence:

How to remove hair dye from a wall
Test the alcohol on a small area.
Wet a cotton ball with alcohol and rub it on an inconspicuous spot on the wall, first. Check for stains, discoloration, or residue.

Choose from:
[A]. If the alcohol does not come off with rubbing, there could be alcohol fumes in the air. Run a hairdryer over the spot to rinse it down.;
[B]. If it returns to a lighter hue after using alcohol, there may be a problem. Apply more alcohol to see if the area is dry.;
[C]. Wash the cotton ball in dirty water and dry it on a towel. Set this on the stain and rub it a second time.;
[D]. If the alcohol produces any unwanted affects, then try a different method. You should always test products and solutions on small, hidden areas first before using them on larger surfaces to avoid unwanted effects.;
The answer is:
[D].