What does qos pre-classify provides inregardto implementing QoS over GRE/IPSec VPN tunnels？（）

A. enables IOS to copy the ToS field from the inner （original） IPheader to theouter tunnel IP header
B. enables IOS to make a copy of the inner （original） IP header and to run a QoS classification before encryption， based on fields in the inner IP header.
C. enables IOS to classify packets based on the ToS field in the inner （original） IP header
D. enables IOS to classify packets based on the ToS field in the outer tunnel IP header
E. enables the IOS classification engine to only see a single encrypted and tunneledflow to reduce classification complexity