The correct answer is Option 4: the Constitution of India.
Agricultural income-tax is assigned to the State Governments by the Constitution of India. The Constitution of India, which was adopted in 1950, is the supreme law of the land and provides the framework for the governance of the country. It outlines the division of powers between the central government and the state governments.
In the case of agricultural income-tax, it falls under the purview of the state governments as per the Constitution. The Constitution of India empowers the state governments to levy and collect taxes on agricultural income within their respective territories. This power is derived from the provisions of the Constitution, specifically under Article 246(3) and Entry 46 of List II (State List) of the Seventh Schedule.
Article 246(3) of the Constitution of India states that the state legislatures have the power to make laws with respect to any matter enumerated in the State List. Entry 46 of List II specifically includes "Taxes on agricultural income" as one of the matters on which the state legislatures have the power to make laws.
This provision gives exclusive authority to the state governments to levy and collect taxes on agricultural income. It is important to note that agricultural income-tax is separate from income tax, which is levied by the central government.
The other options mentioned in the question - the Finance Commission, the National Development Council, and the Inter-State Council - do not have the specific mandate to assign agricultural income-tax to state governments. These institutions play different roles in the governance and financial management of the country, but they do not have the power to assign specific taxes to state governments.
To summarize, the Constitution of India assigns the power to levy and collect agricultural income-tax to the state governments. This authority is derived from the provisions of the Constitution, specifically Article 246(3) and Entry 46 of List II of the Seventh Schedule.