Which one of the following conditions would not result in a certificate warning during a vulnerability scan of a web server?
a. Using a valid SSL/TLS certificate issued by a trusted Certificate Authority
b. Ensuring that the server's SSL/TLS configuration does not allow weak protocols or ciphers
c. Keeping the SSL/TLS certificate and its private key secure and not publicly accessible
d. Enabling server-side certificate validation and ensuring the server's hostname matches the certificate's Common Name (CN)
