Explanation:

According to Article $324(2)$ of the Indian Constitution, the Chief Election Commissioner and other Election Commissioners are appointed by the President of India. While the Constitution lays down the framework (Option 1) and Parliament may enact laws to regulate the conditions of service and tenure (Option 2), the actual appointing authority is the President. The Prime Minister (Option 4) plays a role in advising the President, but the constitutional power of appointment rests with the President. The tenure is also determined by the President, subject to constitutional provisions ($6$ years or until the age of $65$, whichever is earlier). Therefore, (3) The President is the correct answer.