How is a unitary system of government different from a federal system?

A. In a unitary system, all powers are held by one government.
B. In a unitary system, most powers are reserved to provincial governments.
C. In a federal system, there are no checks and balances between branches of government.
D. In a federal system, the head of the executive branch and the legislative branch are the same person.

A. In a unitary system, all powers are held by one government.