For the first question, the correct answer is:
O b reserved powers
Reserved powers refer to those powers that are not specifically granted to the National Government by the Constitution and are not prohibited to the States, thus they are "reserved" for the States.
For the second question, the best answer is:
shape a strong central government while preserving local self-government.
The principle of federalism allowed the Framers to create a system that balanced power between the national and state governments, thereby enabling a strong central government while allowing for local governance.