When ad campaigns are optimized by Google’s AI, what does that

It means they use AI and machine learning technology to predict what will achieve the best conversion outcomes to optimize bidding, creative, etc.
It means they use basic tasks, then software, to automate those tasks, and the process has all the necessary data.
It means they use rules-based attribution and software to achieve desired AI-friendly outcomes to influence the process and avoid optimizing for those outcomes.
It means they use data-driven attribution to automate tasks, and the process has all the necessary data.

When ad campaigns are optimized by Google’s AI, what does that mean?