In a federal system of government, power is divided by the Constitution between the central government and the state governments. Both levels of government are independent in their own spheres, and state governments are not subordinate to the centre.
In a unitary system of government, all powers are concentrated with the central government. State or local governments function under the authority of the centre and can be ordered, changed, or abolished by it.
Therefore, the correct option is C, because it correctly states that state governments in unitary systems are subordinate to the central government.