How did the Central Powers get their name ?

Explanation:

The name "Central Powers" comes from the location of the main countries in the alliance. They were centrally located in Europe between Russia to the east and France and Britain to the west.

i beleive a. is the only possible answer

the doctrine of nullification recommended that states living inside the union have the one-sided, inalienable ideal to void any law made by the national government that could be esteemed illegal.

the united states was shaped based on a general agreement among its individual states. hence, it is inferred that under the hypothesis of invalidation, since the states are the establishment of the union, they have the ability to referee and disprove unlawful laws.