Choose the true statement regarding QoS pre-classify.（）
- AQoS pre-classify permits making QoS decisions based on elements from the unencrypted IP packet.
- BQoS pre-classify is required when encrypting voice.
- CQoS pre-classify is an advantage to Service Providers transporting encrypted packets.
- DQoS pre-classify is not designed for IPSec/GRE configurations.