C.to limit the powers of the central government by establishing reserved powers for states and individuals
Performance-in-public syndrome is the right answer because John is having issues playing when he is in pubic but not when he is alone, therefore playing in front of other people is causing John the anxiety.
I believe the answer is: Explain
Explain is the act of figuring out how things turn out as it is. In scientific field, to obtain proper explanations, researchers need to construct a hypothesis and tested them with proper scientific method in order to find relevant facts that might connected to the occurrence.
I would say the Louisiana purchase because it doubled the size of the U.S.