Your ad can show on the Google Search Network when someone searches for terms that are similar to your:

Your ad can show on the Google Search Network when someone searches for terms that are similar to your:

• Keywords
• Placements
• Website
• Ad text

Correct answer is:

• Keywords

Explanation: Your ad can be shown on the Search Network when someone searches for terms that are similar to your keyword. This is how search network campaign work.When someone searches on Google, your ad could be eligible to appear based on the similarity of your keywords to the person’s search terms, as well as your keyword match types. Keywords are also used to match your ad to sites in the Google Network that are related to your keywords and ads.

Read more here: https://support.google.com/adwords/answer/6323?hl=en