Ad groups should be used to:

Ad groups should be used to:

A) organize your ads by a common theme, such as the types of products or services you want to advertise
B) manage your daily budget according to which keywords are a priority
C) control delivery of your ads so that they appear only to users in a specific geographic location
D) control the specific sites that your ad will be targeted to on the Google Display Network.

Answer - organize your ads by a common theme, such as the types of products or services you want to advertise