This spring, Bill, who has worked for the City of Hortonville for just over three years, plans to spend the entire three weeks of paid vacation to which he is entitled this year with his family. Anyone who has worked for the City of Hortonville from between one and four years is entitled to two weeks paid vacation each year but can apply up to half of any vacation time that remains unused at the end of the year to the next year' s vacation, as long as the unused vacation time is not more than eight weeks. If the statements above are all true, which one of the following must also be true on the basis of them? ['Bill had exactly two weeks of vacation left unused at the end of last year.', 'Bill did not have any vacation time left and the end of his first year.', 'Bill will never have eight weeks of vacation time.', 'Bill has used one week of vacation time each year for the past two year.']