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

A.
smtpd_tls_cert_file, smtpd_tls_key_file, smtpd_tls_CAfile, smtpd_use_tls

B.
smtpd_tls_key_file, smtpd_tls_CAfile, smtpd_use_tls, smtpd_tls_pem_file

C.
smtpd_tls_CAfile, smtpd_use_tls, smtpd_tls_pem_file, smtpd_tls_cert_file