In the IS-IS network referenced in the exhibit, you must perform route leaking from the backbone.
What is necessary to accomplish this task?

A.
Configure a policy accepting all routes from Level 2 to Level 1 and apply as import to IS-IS on R3 and R4

B.
Configure a policy accepting all routes from Level 2 to Level 1 and apply as export to IS-IS on R2

C.
Configure a policy accepting all routes from Level 2 to Level 1 and apply as import tp IS-IS on R2

D.
Configure a policy accepting all routes from Level 2 to Level 1 and apply as export to IS-IS on R3 and R4