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

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_pem_file

C.
smtpd_tls_CAfile, smtpd_use_tls, smtpd_tls_pem_file, smtpd_tls_cert_file

D.
smtpd_use_tls, emtpd_tls_pem_file, smtpd_tls_cert_file, smtpd_tls_key_file