• 2 hours
• 4 hours
• 8 hours
• 24 hours

The correct answer is: 24 hours

Explanation: When you create a data exclusion event, you can specify a time range that is anywhere from one hour to a whole year. Even though you can specify a time range that is less than 24 hours, Search Ads 360 will always exclude data for the entire 24 hours. Also note that Search Ads 360 converts your local time zone which is shown in the user interface into the engine time zone when excluding data.

Read more here: https://support.google.com/searchads/answer/6149075