Zoya is analyzing their recent campaign, and notice that certain supply sources are performing better than others across key metrics. What would be the best way to optimize their campaign?

The selected answer Remove underperforming supply sources or sites is correct because when analyzing campaign performance, it is crucial to focus resources on the highest-performing supply sources. If certain sources or sites are not contributing effectively to the campaign’s key metrics, removing them allows the budget to be reallocated to the more successful sources, optimizing the campaign’s overall performance. Increasing bids on underperforming sources may not be as effective, as it could lead to inefficient spending without addressing the root cause of the poor performance. Reducing the number of audiences is also not necessarily helpful in this case, as it does not directly address the issue of supply source performance. Therefore, removing underperforming supply sources ensures that the campaign is more focused and efficient.