Box 1 – Banner ad unit
Box 2 – Interstitial ad unit
Box 3 – Rewarded ad unit
Box 4 – Native ad unit
Box 1 only has an option for Ad type and nothing else. It is the simplest one that’s why it is for the Banner ad unit.
Box 2 has Ad type, Frequency Capping, and eCPM floor. This is found only in the Interstitial ad unit.
Box 3 has an additional setting called Reward settings so this is used for the Rewarded ad unit.
Box 4 has an additional setting called Media type which is only found in the Native ad unit.
This question is from the Check your Knowledge section of the “Configure ad units with AdMob” lesson from the “Manage Ad Formats and Inventory with AdMob” unit which is a part of the Get Started with Google AdMob course.