YouTube videos are consuming too much bandwidth on the network, causing delays in mission-critical traffic. The administrator wants to throttle YouTube traffic. The following interfaces and zones are in use on the firewall:
ethernet 1/1, Zone: Untrust (Internet-facing)

ethernet 1/2, Zone: Trust (client-facing)

A QoS profile has been created, and QoS has been enabled on both interfaces. A QoS rule exists to put the YouTube application into QoS class 6. Interface Ethernet 1/1 has a QoS profile called Outbound, and interface Ethernet 1/21 has a QoS profile called Inbound.
Which setting for Class 6 will throttle YouTube traffic?
Correct Answer: B
Explanation/Reference:
Identify the egress interface for applications that you identified as needing QoS treatment.
The egress interface for traffic depends on the traffic flow. If you are shaping incoming traffic, the egress interface is the internal-facing interface. If you are shaping outgoing traffic, the egress interface is the external-facing interface.
References: https://www.paloaltonetworks.com/documentation/61/pan-os/pan-os/quality-of-service/ configure-qos