Multi-choice problem: Continue writing the next sentence in this paragraph:

How to remove rust from cement
Rinse and wash the concrete with soap and water before beginning.
Dirt and dust will just get between your cleaner and the stain, making your work less effective. Once you've cleaned the surface of the concrete you should let it dry before moving on.

Pick from:
(A). For concrete floors, you could create some special cleaning mix with five ml powdered metal glue and three tablespoons brass nitrate. Take your cement stain and water mixture out of the container and mix it with quarter-cup disposable plastic bags.;
(B). Before buffing, run soapy water over the surface of the concrete to try and dislodge anything that may be stuck to it. Keep an eye on it as you scrub to make sure you don't dislodge any thin areas, like cracks or grooves.;
(C). Pour or spray lemon juice on the rusted surface. Almost all rust remover uses acid to lift and scrub away the stain, and the high concentration of citric acid in pure lemon juice makes it a worth-while cleaning candidate.;
(D). Measure your area to get a rough idea of how big the area you're cleaning should be. Start by taking a measuring tape and writing down the measurements on a piece of paper.;
(C).