Which activity provides a stronger signal of an ad's impact on a conversion.

The correct answer is Post-click conversion because it provides a stronger signal of an ad's impact on a conversion. A post-click conversion occurs when a user clicks on an ad and subsequently performs a desired action, such as making a purchase or signing up. The click signifies a direct interaction with the ad, making the conversion more attributable to the ad itself. In comparison, post-view conversions (where the user simply views the ad without clicking) or pre-view conversions (where no ad interaction occurs) offer less direct evidence of the ad's effectiveness, as they do not involve the user taking action based on an ad engagement. Therefore, post-click conversions provide the clearest and most direct signal of the ad’s influence on the user's decision to convert.