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

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. And 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.