Which two statements are correct regarding units in JUNOS?（）

• A、Units in JUNOS are always required for any interface configured with logical addresses such as IP and IPv6.
• B、Units in JUNOS are only required when you are configuring sub-interfaces for inter-VLAN routing.
• C、Unit numbers must match the DLCI or VCI numbers configured on the interface.
• D、Unit 0 is the only value allowed on interfaces running HDLC, PPP, or for Ethernet interfaces not doing VLAN-tagging.