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

How to get water stains off a ceiling
Find the source of the moisture.
You may find an obvious leak in a pipe or fixture on the floor above the damaged ceiling, but it may also be more difficult to pinpoint.
If you don't locate the source of the moisture prior to doing the repair, the problem will just keep coming back.

Choose from: (a). Wear gloves, safety glasses and a dust mask while looking for and repairing the leak. Depending on how long the leak has gone unrepaired, there could be mold present.; (b). This can only be prevented by replacing a leaking leak with another fixture. Moisture generated by a leak will also lead to damage.; (c). If the leak is recurring, then you probably need to get rid of it before it lingers. You can sort out the leak by calling a mechanic or an electrician if you have no problem figuring out what's causing the problem.; (d). Luckily, small water leaks are usually removed by scraping away the grime and dirt with a razor blade and a plunger. Vent fans may also be able to circulate ventilation through a damaged ceiling.;
(a).