For advertisers bidding on a maximum CPC basis, Quality Score on the Display Network is evaluated on the:

1. Quality Score of keywords across all campaigns and all ad groups
2. clickthrough rate (CTR) of all keywords across the account and relevance of the ad text and keywords to the advertiser’s landing page
3. Quality Score of all campaigns and regional targeting settings
4. click–through rate (CTR) of the ad and relevance of the ad text and keywords to the publisher’s site

Correct Answer:
clickthrough rate (CTR) of all keywords across the account and relevance of the ad text and keywords to the advertiser’s landing page