A. The route reflectors must have a private AS number.
B. The route reflectors must have an EBGP peering session between each other.
C. The route reflectors must have a cluster ID configured.
D. The route reflectors must have a different AS number than the clients.
Explanation:
Reference: https://www.juniper.net/documentation/en_US/release-independent/nce/topics/example/ routing-protocol-bgp-security-route-reflector-configuring-cli.html