Before applying polish, what should you ask the client to do?

The most appropriate action to take before applying polish is to ensure the client has their car keys out. This is important because it allows the client to make an easy exit once their nails are finished drying without smudging the polish. Timing is crucial in nail services, and preparing the client for when the appointment is complete can enhance the overall experience.

In the context of the other options, while having clients remove jewelry or apply cuticle oil might be part of the nail preparation process, they are typically done before the actual polish application starts. Choosing a nail design, although an enjoyable part of the service, is not a practical step directly related to the application process of polish. These can be seen as preparatory steps that do not directly impact the immediate act of polishing the nails.