Definition: This task is about writing a correct answer for the reading comprehension task. Based on the information provided in a given passage, you should identify the shortest continuous text span from the passage that serves as an answer to the given question. Avoid answers that are incorrect or provides incomplete justification for the question.
Input: Passage: Changes to DST rules cause problems in existing computer installations. For example, the 2007 change to DST rules in North America required many computer systems to be upgraded, with the greatest impact on email and calendaring programs; the upgrades consumed a significant effort by corporate information technologists. Question: What year did DST rules change in North America?
Output:
2007