It is binding on the Supreme Court to give its opinion on any matter referred to it by the President. This is correct, as per Article 143 of the Indian Constitution, the President can refer any question of law or fact to the Supreme Court for its advisory opinion, and the Supreme Court is bound to give its opinion on such a reference.
The opinion given by the Supreme Court on a reference under advisory jurisdiction is not binding on the government. This is also correct, as the advisory opinion given by the Supreme Court is not binding on the government or any other authority. It is merely an opinion provided by the court on a reference made to it.
Option 2 is incorrect, as it is not necessary for the full bench of the Supreme Court to hear a reference made under its power of advisory jurisdiction. It can be heard by a bench of any size as deemed fit by the Chief Justice of India.
Option 4 is also incorrect, as there is no such limitation on the number of references that can be made to the Supreme Court under its power of advisory jurisdiction.