Which two statements are correct with regard to route distinguisher as defined in RFC 4364-AKA IP-VPN(MPLS-VPN)?

Which two statements are correct with regard to route distinguisher as defined in RFC 4364-AKA IP-VPN(MPLS-VPN)?

A.
Route-Distinguisher is an 8 byte value used in creating unique VPNv4 address.

B.
Route-Distinguisher is an 8 byte BGP attribute value used in influencing BGP best path algorithm.

C.
The configuration to define Route-Distinguisher is:
Ip vrf bulle
Rd 1:1

D.
A route distinguisher can be imported and exported to and from a VRF