Which step in the advertising supply chain involves the actual performance of the campaign?

The step in the advertising supply chain that involves the actual performance of the campaign is Campaign Delivery and Optimization. This stage is crucial because it encompasses not just the launch of the advertising campaign, but also the monitoring and adjustment of that campaign to improve its effectiveness and achieve the desired outcomes. During this phase, marketers track performance metrics, assess audience engagement, and make real-time enhancements to the ad delivery based on analytical insights.

Creative Delivery focuses on producing and distributing the creative elements of the campaign rather than executing and measuring its performance. Billing and Collections pertain to the financial aspects of advertising, handling payments and revenue management, which don’t directly involve the campaign's execution. Market Research is conducted prior to a campaign's launch to gather insights about the target audience and market trends, but it does not involve the live performance of the advertising efforts. Thus, Campaign Delivery and Optimization is the correct choice as it is the point where the campaign is actively running and being evaluated for effectiveness.