The error message indicates an MD5 authentication failure between the two BGP peers. The IP addresses involved are 10.10.10.1 and 10.120.10.1, which should correspond to R1 and R2 respectively. The correct configurations to resolve this issue would be to ensure that both routers are configured with the same password for MD5 authentication within the same peer group CORP. Option A is correct because it configures R1 with the CORP peer group and sets the password to "Cisco" for MD5 authentication. Option E is correct because it configures R2 with a neighbor in the CORP peer group at IP address 10.10.10.1 (which should be R1) and sets the password to "Cisco" for MD5 authentication. References := Implementing and Operating Cisco Service Provider Network Core Technologies