Which Following Statements About the Four-Step QoS Process (Classification, Queuing

Which following statements about the four-step QoS process (classification, queuing, scheduling, and marking/remarking) executed for every packet entering a Nokia 7750 SR is TRUE?

A) The process happens only before the packet goes through the switching fabric.
B) The process happens only before the packet goes onto the egress port.
C) Marking/remarking the packets is for future classification.
D) Marking/remarking the packets will occur right after classification of the packet.