Which two statements are true about an interconnect logical system on an SRX Series
device? (Choose two.)
A.
The root and user LSYSs connect to the interconnect LSYS using vt interfaces.
B.
VPLS is used to switch inter-LSYS traffic.
C.
VXLAN is used to switch inter-LSYS-traffic.
D.
The root and user LSYSs connect to the interconnect LSYS using lt interfaces.
http://www.juniper.net/techpubs/en_US/junos12.1×47/topics/task/configuration/logical-systems-master-config-overview.html
B and D are indeed correct:
https://www.juniper.net/techpubs/en_US/junos12.1/topics/concept/logical-systems-interfaces.html