Which statement about federal and unitary systems is most accurate?

In a federal system, power is concentrated in the states; in a unitary system, it is concentrated in the national government.

In a federal system, the constitution allocates powers between states and federal government; in a unitary system, powers are lodged in the national government.

Today there are more countries with federal systems than with unitary systems.

The United States and Japan have federal systems, while Great Britain and Canada have unitary systems.

In a federal system, the constitution allocates powers between states and federal government; in a unitary system, powers are lodged in the national government.

Explanation:

Federalism is a political doctrine that seeks to be formed by organizations (states) that are associated by delegating some liberties or powers of their own to another higher body (federal government), to whom sovereignty belongs and that retain a certain autonomy, since some powers belong exclusively to them.

On the other hand, unitarianism is a political doctrine favorable to the unity and centralization of power between regions of the same state or between states that belong to the same international political community.