when configuring a route target that there are implementation issues with some IOS levels that require _______?

Be aware when configuring a route target that there are implementation issues with some IOS levels that require _______?

A.
All export RT’s must have a matching import RT for the same VRF.

B.
There must be at least one import RT.

C.
At least one export RT must also be an import route target for the same VRF.

D.
There must be at least one RT.