Which of these analyses can be accomplished with an overlap query?

The correct answer is Determining how a first-party uploaded audience compares to Amazon audiences because an overlap query is specifically designed to analyze the intersection or overlap between different audiences. In this case, it can help determine how a first-party uploaded audience compares to Amazon's audiences, revealing where there are common or shared users across both groups. This type of analysis is useful for understanding audience reach and identifying overlaps in targeting. The other options, such as generating delivery metrics per Amazon audience or per campaign and per line item, are typically accomplished through other types of queries or analysis tools, and not specifically through an overlap query, which focuses on comparing audiences and their shared attributes.