Explanation
The network 20.0.0.0 0.0.0.255 area 0 command on R2 did not cover the IP address of Fa1/1 interface of R2 so OSPF did not run on this interface. Therefore we have to use the command network 20.1.1.2 0.0.255.255 area 0 to turn on OSPF on this interface.
Note: The command network 20.1.1.2 0.0.255.255 area 0 can be used too so this answer is also correct but answer C is the best answer here.
The network 0.0.0.0 255.255.255.255 area 0 command on R1 will run OSPF on all active

Explanation
There are five basic device roles in the fabric overlay:
+ Control plane node: This node contains the settings, protocols, and mapping tables to provide the endpoint-to-location (EID-to-RLOC) mapping system for the fabric overlay.
+ Fabric border node: This fabric device (for example, core layer device) connects external Layer
3 networks to the SDA fabric.
+ Fabric edge node: This fabric device (for example, access or distribution layer device) connects wired endpoints to the SDA fabric.
+ Fabric WLAN controller (WLC): This fabric device connects APs and wireless endpoints to the SDA fabric.
+ Intermediate nodes: These are intermediate routers or extended switches that do not provide any sort of SD-Access fabric role other than underlay services.

Lines (CON, AUX, VTY) default to level 1 privileges.

Explanation
he first figure is the output of the "show control connections" command. From this figure we learned that the
192.168.100.82 so we need to connect to this IP address (not 192.168.100.80).