The correct answer is option 4: Union of States. The Cabinet Mission Plan for India, proposed by the British government in 1946, aimed to address the issue of governance and the transfer of power from the British to Indian hands.

The plan proposed a federal structure for India, where power would be divided between the central government and the provinces. However, it differed from a traditional federation by proposing a strong center with more powers than the provinces. This union of states would ensure a balance between central authority and regional autonomy.

Option 1, Federation, is similar to the concept proposed by the Cabinet Mission Plan, but it fails to capture the specific emphasis on a strong central government.

Option 2, Confederation, is not the correct answer. A confederation involves a weak central authority and strong regional or state governments, which is not in line with the Cabinet Mission Plan.

Option 3, Unitary form of Government, is also incorrect. A unitary government is centralized, with all powers held by a single central authority, which contradicts the principles of the Cabinet Mission Plan.

Alert - correct answer should be option 4.