Refer to the exhibit. Which per-hop QoS behavior is R1 applying to incoming packets?

Marking is the act of classifying packets by adding a QoS tag (e.g., CoS, DSCP) to them, which typically occurs earlier in the QoS process and isn't the direct per-hop behavior of handling packets for transmission.

Shaping buffers excess traffic and smooths the output rate to a configured value, typically applied to outgoing traffic over a period, rather than the immediate per-hop handling of incoming packets.

Queuing is a fundamental per-hop QoS mechanism that involves placing packets into different queues based on their classification and then scheduling their transmission according to a configured algorithm, directly influencing how traffic is handled to mitigate congestion.

Policing enforces a maximum rate by dropping or re-marking packets that exceed the threshold, which is about enforcing limits rather than the general per-hop behavior of packet scheduling and management.