What is the most logical next event?

How to clean a humidifier filter 
Unplug your humidifier. 
Before you disassemble your humidifier unit, make sure it's turned off and disconnected from the wall outlet. You're going to be handling a lot of wet parts, so this will help you prevent any accidents or damage.

Choices: A. In warm, dry environments, the temperature should never exceed 103 ° f (16 ° c). If it is warmer than this, try the open air humidifier.; B. Choose a humidifier meant for use on bedroom and living room walls. Some humidifiers come with built-in, no-calve-type, filters.; C. Choose a flat, water-resistant surface as your work area. A countertop near the sink is optimal.; D. To remove the humidifier from the outlet, reach into the chamber and locate the face of the handle. Without removing the handle, disconnect the unit from the wall outlet.;
C.