BGP route target filtering can be configured on PE devices or on route reflectors (RRs). Configuring BGP route target filtering on RRs is more efficient and scalable, as it reduces the number of BGP sessions and updates between PE devices. To configure BGP route target filtering on RRs, the following steps are required: Configure the family route-target statement under the BGP group or neighbor configuration on the RRs. This enables the exchange of the route-target address family between the RRs and their clients (PE devices). Configure the resolution rib bgp.l3vpn.0 resolution-ribs inet.0 statement under the routing-options configuration on the RRs. This enables the RRs to resolve next hops for VPN routes using the inet.0 routing table.

C is not required, because "resolution rib bgp.l3vpn.0 resolution-ribs inet.0" is only required for RR's that are not on the LSP, in the diagram it shows it is on the LSP, hence can resolve next-hops as it has access to the inet.3 table. The Route Target family needs to be on the PE's and the RR's

B & D are correct

BD is correct. You need to configure the family route-target on both PEs and RR.