Which of the following statements are true? I. Presidential election is held before the expiration of the term of the outgoing President. II. The term of the President's office can be extended if general elections for any Assembly are not held due to an emergency. III. If the term of any President is cut short by reason of his death, resignation or removal, then the election of next President should be held within three months of the occurence of the vacancy. IV. The Indian Constitution is silent on the number of times a person can be re-elected President.