一位营销者可能使用自适应展示广告的两个原因是什么？请选择两项。

Responsive Display Ads (RDAs) offer two key advantages. First, they are cost-effective because they can generate more conversions at a comparable cost-per-conversion compared to other display ad formats. This efficiency stems from their ability to adapt and perform well across various placements. Second, RDAs provide expanded reach. They automatically adjust their size, appearance, and format to fit almost any ad space, including both native and non-native inventory. This adaptability ensures your ads can appear in more places, maximizing visibility. "Improved communication" is incorrect because RDAs do not use automated voice systems or text to respond to visitor queries; that describes a chatbot or customer service tool, not an ad format. "Guidance" is also incorrect; RDAs automatically adjust, they don't guide users on how to manually resize or format ads.