Securing an Autonomous Database after a user departs involves:

Correct Answer (C): “Rotate the instance wallet and share the new wallet with the remaining users” invalidates the old wallet’s credentials (e.g., certificates in ewallet.p12). Since the wallet secures client connections, rotating it ensures the departed user’s access is revoked, even if they retained a copy.

Incorrect Options:

A: Trusting the user is a security risk, not a solution.

B: Deleting the database user ID doesn’t address wallet-based access if credentials were shared externally.