What is the main purpose of QoS classification?

A.
To set fields in IP packets and identify that packet as belonging to a specific class of service.

B.
To signal network devices on which QoS mechanism should be employed to meet the requirements of a particular service class.

C.
To identify traffic as belonging to a specific class of service.

D.
To provide a mapping between link layer and network layer QoS.

Explanation:
Classification is the identifying and splitting of traffic intodifferent classes. Traffic can be classed by various means including the DSCP. Modular QoS CLI allows classification to be implemented separately from policy
The basic purpose of QoS is to identify which class of service traffic belongs to.