Which one of the following is not a feature of Indian federalism

Which one of the following is not a feature of Indian federalism?

1. Courts can interpret the Constitution and powers’ of  different levels of the Government.
2. Sources of revenue for’ the Union Government and the State  Governments are specified.
3. Powers of the Union and the States are specified in the Constitution.
4. Indian federalism is based on the  principle of Separation of Powers.