For number 7 i got b because it says in the first line they "planned" to rob then they actually did rob. My lefal teacher said that as well but idn :/
For 15 i got c because ratify only means to sign the treaty. So they still need to enact legislayion before they can enforce it
For 18, my teacher n i said it was c because there is no such thing as transnational law. Theres only transnational crimes
Lastly, for 20 i got b but cant remember what the teacher said :/