Which of the following parameters should be set in main.cf to enable TLS in Postfix?

Enabling TLS in Postfix requires `smtpd_tls_cert_file` to specify the path to the server's public certificate, `smtpd_tls_key_file` for the corresponding private key, `smtpd_tls_CAfile` for the file containing trusted Certificate Authority certificates, and `smtpd_use_tls` to explicitly turn on TLS support for incoming SMTP connections.

The `smtpd_tls_pem_file` parameter is not a standard or required setting for basic TLS configuration; it is typically covered by `smtpd_tls_cert_file` and `smtpd_tls_key_file`.

The `smtpd_tls_pem_file` parameter is not a standard or required setting for basic TLS configuration; it is typically covered by `smtpd_tls_cert_file` and `smtpd_tls_key_file`.

The `smtpd_tls_pem_file` parameter is not a standard or required setting for basic TLS configuration; it is typically covered by `smtpd_tls_cert_file` and `smtpd_tls_key_file`.