After increasing the MTU size of an interface and committing the configuration, the command to verify the applied MTU change is D, "show interfaces ge-0/0/0." This command displays detailed information about the interface, including the current MTU size, making it the best choice for verifying the applied changes.

To convert the decimal number 7 to binary, the correct representation is 00000111 (C). In binary, 7 is represented as 1+2+4 (2^0 + 2^1 + 2^2), which corresponds to the last three digits being 1 in the binary format, with leading zeros added for clarity.

To view real-time usage statistics for the busiest interfaces on a device running Junos OS, the correct command is B, "monitor interface traffic." This command provides a dynamic, real-time view of the traffic flowing through the interfaces, allowing administrators to quickly identify and monitor the busiest interfaces on the device.

In the exhibit shown, the highlighted number next to the route type (Static) within the square brackets indicates the route preference, also known as the administrative distance. In Junos, the route preference is a value that determines the priority of the route source. Lower numbers indicate a higher priority when the routing table is being calculated. The route preference is used to select the best route when multiple paths to the same destination exist from different routing sources. The number 5 is unusually low for a static route by default, suggesting it has been manually configured to override other route types.

Class of Service (CoS) in Junos OS provides tools for managing traffic congestion and ensuring that latency-sensitive traffic is given priority over less time-critical data. By implementing CoS, network administrators can classify traffic into different priority levels, apply scheduling policies to ensure that high-priority traffic is transmitted first, and use congestion management techniques such as queue buffers and drop profiles. This helps in maintaining the quality of service for critical applications, especially during periods of high network congestion. However, CoS does not eliminate congestion entirely nor does it inherently make the network faster; it provides a mechanism for better managing and controlling traffic flows according to their importance and time sensitivity.