i think there is an argument that it could be c, because native title simply means, "the right to live on land to which one has such title and use it for traditional purposes" now this wasn't recognised in AUSTRALIAN law until the mabo case, however it was always a feature of customary law?
also it doesn't explicitly state ATSI customary law, so the answer should be applicable to any form of customary law, which includes international customary law and is dispute resolution a part of this? i don't really know the answer to that but i think Native title is definately part of customary law, i guess it's just whatever the board deems most correct!
although i definately would not say this was the easiest question