You can use audience targeting to show your ads to:

  • specific websites, based on specific interests
  • groups of websites, based on specific interests
  • specific groups of people, based on their interests
  • specific groups of people, based on their location

The correct answer is:

  • specific groups of people, based on their interests

Explanation: Audiences: Depending on your advertising goals, you can choose the audience that best matches your customers. To drive brand awareness, use affinity audiences to reach TV-like audiences on a broad scale. To reach as many potential customers as possible with an affinity for a specific product area, you might try adding custom affinity audiences. To reach specific audiences actively shopping for a product or service, use in-market audiences instead.

Read more here: https://support.google.com/adwords/answer/2404191?hl=en