What must a user have to be able to upgrade macOS on their iMac?

Upgrading macOS requires volume ownership, tied to an admin account with permissions to modify the system volume. ThemacOS Deployment Referencestates, "To install or upgrade macOS, the user must have volume ownership, which allows the system to authenticate the operation against the secure volume." Option B is for MDM updates, C is insufficient alone in newer macOS versions, and D is for content, not upgrades.