Unicast Reverse Path Forwarding （Urpf ） can work in the following modes：（）

A.Multicasting
B.Global addressing
C.Forward-explicit congestion notification （FECN）
D.Virtual circuit status messages.
E.Backward-explicit congestion notification （BECN）

A.Loss should be no more than 1 percent.
B.One-way latency should be no more than 150 ms
C.Jitter should be no more than 30 ms
D.Loss should be no more than 3 percent
E.One-way latency should be no more than 150/2=75 ms
F.Jitter should be no more than 300 ms

A.AF41
B.AF31
C.AF21
D.BE
E.EF