The network shown in the figure below. The host has an ARP cache. Which of the following statements are correct? )(Multiple Choice Questions)

As shown in the figure, the two switches use the default parameters to run STP, the configuration command STP root primary is used on switch A, and the configuration command STP priority 0 is used on switch B.
Then which port will be blocked?

Which of the following are not the characteristics of a small campus network? ()

In the network shown in the figure below, all links are Ethernet links, and all interfaces of all routers run OSPF protocol, how many DRs are elected in the entire network?

The last option field (option) of 1Pv4 is variable-length optional information. What is the maximum length of this field? ()