Final answer:
b. Antiseptic.Antiseptic should never be added to the foot bath with the client's feet as it can cause irritation or an allergic reaction due to its concentrated nature.
Step-by-step explanation:
The chemical that should never be added to the foot bath with the client's feet is b. Antiseptic. Adding antiseptic directly into a foot bath with the client's feet can potentially cause irritation or an allergic reaction due to the concentrated nature of antiseptics.
Options like Epsom salt, vinegar, and essential oils are generally considered safe for use in a foot bath and can provide various benefits such as relaxation, antibacterial properties, or pleasant aroma.
It is important to always dilute these substances appropriately and perform a patch test when using new products to ensure that there is no adverse reaction.