Solution:The Constitution of India introduces a federal system as the basic structure of Government as there is the distribution of Power as given under the seventh schedule of the Constitution and Art. 245-255 which is related to the distribution of Legislative powers.However, features like single Citizenship, Appointment of Governors by Presidents, Power of the Parliament to legislate on any matter of state list in a time of Emergency (Article 250), Power of Parliament to legislate on a matter of state in the national interest (Art 249) shows a strong Unitary System.
Statement 1 and 2 are correct and 3 and 4 are wrong because the state legislature does not have power in reference to Foreign and Defence matters. This power comes under the Union Parliament. So, only Union is sovereign not the States.
There is only hierarchy in the Judicial system not the division of judicial power between the Union and the state. So option 4 is also wrong.