What does source routing specification allow a sender to do?

The correct answer is that source routing specification allows a sender to specify the route that a packet should follow. This means that when a sender utilizes source routing, they can define the exact path that the packet will take across the network, as opposed to relying solely on the routing tables of the intermediate network devices.

Source routing can be valuable in certain situations, such as when a sender wants to avoid congested areas of the network or when they need to ensure that the packet traverses specific devices or networks for security or compliance reasons. The sender includes the route information within the packet header, dictating the sequence of hops that the packet will take until it reaches its destination.

Other options are focused on different network functionalities: encryption is related to securing data, compression pertains to reducing the data size for efficiency, and monitoring is about obtaining insights into network performance. None of these options relate to the primary function of source routing, which is concerned specifically with route specification.