John is an advertiser concerned about traffic fluctuations in his AdWords for video campaign. What could be a reason for these traffic fluctuations?

John is an advertiser concerned about traffic fluctuations in his AdWords for video campaign. What could be a reason for these traffic fluctuations?

• A) Viewer behavior has changed on the videos or channel being targeted.
• B) There was an increase in searches performed on Google on keywords that John has placed bids.
• C) The Quality Score of the campaign has increased.
• D) John’s “Search campaign” hit the daily budget.