The correct answer is (a) Parliament.
The Constitution of India, Article 3, states that Parliament has the power to form new states and to alter the boundaries of existing states. This power is exercised by passing a law, which must be passed by a majority of the members of both Houses of Parliament and assented to by the President.
The Vice-President is the ex-officio Chairman of the Rajya Sabha, but he does not have any role in the formation of new states. The Governor is the head of the state, but he does not have the power to form new states.
The option (d) is incorrect because Parliament has the power to constitute new states and its determination of boundary vests in Parliament.