下面哪一项是以保护隐私的方式扩充广告策略的有效方法？

The correct answer is finding users similar to your high lifetime value customers and advertising to them. This leverages lookalike audiences, a privacy-preserving method that expands reach by targeting new users who share characteristics with your most valuable existing customers, without directly identifying individuals. This approach optimizes ad spend by focusing on prospects with a higher likelihood of conversion and long-term value. The other options are less effective or privacy-invasive: Targeting users of competitors' products might be effective but doesn't inherently prioritize privacy and can be challenging to implement without infringing on data privacy. Manually creating segmented users is often based on assumptions and can be less efficient or scalable than data-driven lookalike modeling. Targeting users randomly searching keywords in Display and YouTube ads is too broad and inefficient, leading to wasted ad spend and poor targeting.