To improve the performance of an ad group on the Search Network, advertisers should create ad groups containing:

To improve the performance of an ad group on the Search Network, advertisers should create ad groups containing:

  • Keywords that are also included in the ad text.
  • Destination URLs set at the ad group level.
  • At least 50 keywords.
  • Managed placements and keywords.

The correct answer is:

  • Keywords that are also included in the ad text.

Explanation: Use ad groups to organize your ads by a common theme, such as the types of products or services you want to advertise.

You can read more here: https://support.google.com/adwords/answer/2375404