Comprehensive and Detailed Explanation From Exact Extract:

Steel conduit is primarily used to support and protect electrical conductors from physical damage and to provide mechanical protection. It can also serve as an equipment grounding conductor in many applications, but a separate ground wire is sometimes still required depending on code and installation specifics.

Option A is incorrect because steel conduit often acts as the grounding path, so a separate ground wire is not always required.

Aluminum conduit (B) is not commonly used in all the same locations as steel, especially due to corrosion concerns.

PVC conduit (C) is nonmetallic and does not provide a grounding path; a separate ground wire is needed.