Company employees have noticed that the quality of voice calls on their Cisco IP phones is greatly
reduced at various times during the day. After investigating the problem, you notice that the times
when voice quality is reduced coincides with heavy e-mail traffic. Which of the following can you
implement on the firewall to alleviate this problem?

A.
Stateful inspection

B.
Quality of Service (QoS)

C.
Network address translation (NAT)

D.
Resource Reservation Protocol (RSVP)

Explanation: