Question

how should all chemicals be stored?
in a plastic container in the shop’s supply closet
in a clear container
on osha approved shelving
in a clearly marked and approved container or cabinet

Explanation:

Chemicals should be stored safely to prevent accidents and ensure proper identification. Storing in a clearly marked and approved container or cabinet meets safety and identification requirements. Plastic containers in supply closets may not be suitable for all chemicals, clear containers don't guarantee safety or proper labeling, and OSHA - approved shelving is just about the storage location not the container itself.

Answer:

In a clearly marked and approved container or cabinet