You are the network technician of your company. And you have just received a trouble ticket stating that three calls have successfully been made across a WAN link. However, when making the fourth call, the quality of all calls is lowered. Which QoS mechanism can prevent this problem?

A.
FRF.12

B.
Call Admission Control (CAC)

C.
Link Fragmentation and Interleaving(LFI)

D.
Low Latency Queuing(LLQ)

E.
Priority Queuing