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

CoPP protects the route processor on network devices by treating route processor resources as a separate entity with its own ingress interface (and in some implementations, egress also). CoPP is used to police traffic that is destined to the route processor of the router such as:
+ routing protocols like OSPF, EIGRP, or BGP.
+ Gateway redundancy protocols like HSRP, VRRP, or GLBP.
+ Network management protocols like telnet, SSH, SNMP, or RADIUS.

Therefore we must apply the CoPP to deal with SSH because it is in the
management plane. CoPP must be put under "control-plane" command.