Option (1) is incorrect: The constitution of India is not highly federal.
Option (2) is incorrect: The constitution of India is partly federal and partly unitary.
Option (3) is incorrect:The constitution of India is not highly unitary.
Option (4) is correct: In a federal set up, there is a two tier Government with well assigned powers and functions. A unitary system is governed constitutionally as one single unit, with one constitutionally created legislature.