What are two of the three predefined classes for the Cisco SDM wizard？（）

A.end-to-end network delay times that exceed 50 ms for real-time traffic are considered unacceptable
B.end-to-end network delay times that exceed 250 ms for real-time traffic are considered unacceptable
C.end-to-end network delay is not a factor as long as the  delay is consistent
D.some packet loss can be corrected by codec algorithms
E.RSVP handles voice packet retransmission
F.fragmentation is a result of packet loss

A.analog trunks that provide the Survivable Remote Site Telephony (SRST) feature 
B.analog trunks that provide VoIP gateway functionality 
C.analog trunks that connect a gateway to plain old telephone service (POTS) device such as analog phones, fax machines, and legacy voice-mail systems  
D.analog trunks that connect a gateway to a central office (CO) or private branch exchange (PBX)

A.sampling
B.packetization
C.quantization
D.serialization