The correct answer is option 4, Parliament. When a new state is to be admitted to the Union of India, the process is carried out by the Parliament. Parliament, which consists of the Rajya Sabha (Council of States) and the Lok Sabha (House of the People), plays a crucial role in India`s federal system of governance. The President, although the head of state, does not have the authority to admit a new state to the Union. The Supreme Court, on the other hand, is responsible for interpreting the Constitution and ensuring the legality of actions taken by the government, but it does not have the power to admit new states. Similarly, while the Prime Minister is a key figure in the government, the power to admit new states lies with the Parliament.