Which two statements about the best effort model for QoS are true? (Choose two)

A.
Delay sensitive packets are given preferential treatment.

B.
The default policy identifies a delay sensitive class and a default class.

C.
The default policy identifies a delay sensitive class, best effort class, and a default class.

D.
The model is highly scalable.

E.
The model is still predominant on the Internet.

F.
The model provides guaranteed service.