The correct answer is option 4, President. The Chief Justice of the Supreme Court is appointed by the President of India. The President has the authority to appoint judges to the Supreme Court and the Chief Justice is selected from among the judges of the court. This appointment is based on the recommendation of the collegium, which consists of the Chief Justice and four senior-most judges of the Supreme Court. It is important to note that the Prime Minister, Speaker of the Lok Sabha, and Chairman of the Rajya Sabha do not have the authority to directly appoint the Chief Justice of the Supreme Court. Therefore, option 1, 2, and 3 are incorrect in this context.