Need fast please answer

the statement that best explains why the tenth amendment reserves some rights and powers to states is that the framers believed in the principle of federalism. this principle says that some powers are in the hands of a centralized national government, while others are reserved for the governments of several states.

1# the answer is c

2#the answer is a

i think the answer would mist likely be an adjective clause, because unhappy is an adjective.