Comprehensive and Detailed in-depth Step-by-Step Explanation:

In an Intermediate System to Intermediate System (IS-IS) network, aDesignated Intermediate System (DIS)is elected on broadcast networks to perform the following functions:

Represent the broadcast network as a pseudonode.

Generate and update the Link State Protocol Data Units (LSPs) for the pseudonode.

The DIS is elected based on theDIS priorityvalue, which is configured on IS-IS interfaces. If two routers have the same priority, the router with the higher MAC address becomes the DIS.

Thedefault DIS priorityfor IS-IS interfaces is64, which can be modified depending on the network requirements.

Option A (200):Incorrect. This is not the default value.

Option B (64):Correct. This is the default DIS priority value.

Option C (1):Incorrect. This is not the default value.

Option D (100):Incorrect. This is not the default value.