You are conducting a security audit. While reviewing configuration files and logs, you notice logs accepting POP3 traffic, but you do not see a rule allowing POP3 traffic in the Rule Base. Which of the following is the most likely cause?
A. The POP3 rule is disabled.
B. POP3 is accepted in Global Properties.
C. The POP3 rule is hidden.
D. POP3 is one of 3 services (POP3, IMAP, and SMTP) accepted by the default mail object in R77.