Which is one reason the constitution divides powers between the federal government and state governments

The one reason is to limit the power of Federal Government.

This division of authority is referred to as "federalism". The Federal government is very strong, with much power over the states, but at the same time, it is limited to the powers enumerated in the constitution. Powers not delegated to the Federal government, nor prohibited to the States are reserved to the states or to the people.

it is

C. To limit the power of the Federal government