This summer, Jennifer, who has worked at KVZ Manufacturing for just over three years, plans to spend with her family the entire four weeks of paid vacation to which she is entitled this year. Anyone who has worked at KVZ Manufacturing for between one and four years is automatically entitled to exactly three weeks paid vacation each year but can apply up to half of any vacation time that remains unused at the end of one year to the next year' s vacation. If the statements above are all true, which one of the following must also be true on the basis of them? ['If Jennifer continues to work for KVZ Manufacturing, she will only be entitled to three weeks paid vacation next year.', 'Jennifer did not use two weeks of the paid vacation time to which she was entitled last year.', 'Last year Jennifer took only one week of the paid vacation time to which she was entitled.', 'KVZ Manufacturing sometimes allows extra vacation time to employees who need to spend more time with their families.']