43. Sendmail 預設只轉遞來自於郵件主機本機的郵件，若想開放轉遞特定郵件主機的信件，應修改哪些檔案？ (A) /etc/mail/sendmail.conf 及 /etc/mail/access (B) /etc/mail/sendmail.cf 及 /etc/mail/relay (C) /etc/mail/sendmail.cf 及 /etc/mail/access (D) /etc/mail/sendmail.conf 及 /etc/mail/relay