An advertiser is running site visitor, engagement, and actalike audiences in a campaign. It wants to see which audience drives the highest click-through rate (CTR). How should the advertiser obtain this report?

To determine which audience drives the highest CTR, the advertiser should use the "ad reporting" tab in Ads Manager. Within this tab, selecting "Audience" under "Targeting Breakdown" will provide a detailed report showing performance metrics, including CTR, broken down by each audience segment used in the campaign. This allows for direct comparison of CTR across site visitor, engagement, and actalike audiences. Checking ad saves is irrelevant to CTR. Setting a conversion window affects conversion attribution, not audience-specific CTR reporting. The audience insights tab provides demographic and interest data, not performance metrics for specific campaign audiences.