If a date was changed on an item, how can you quickly find out who changed it?

The best approach to finding out who changed a date on an item is to use the Activity Log within that item. The Activity Log provides a comprehensive record of all actions taken on an item, including changes to fields such as dates. It will show you the specific details of when the change occurred and who made it, allowing for easy tracking of modifications.

The other options would not provide the same level of detail or specificity. The comments section may hold discussions related to the item but does not necessarily record changes made to the dates. Checking the main board view might give a broader overview of item statuses but lacks the detailed history of individual changes. Asking teammates may lead to a subjective answer without any formal record, which might not be reliable. Thus, utilizing the Activity Log is the most efficient and accurate method to track down specific changes made to an item.