Use past product viewers as your audience in Amazon Ads to efficiently drive purchase goals by retargeting those who have already shown interest in your products.

• Lifestyle audiences
• Past purchasers who are not subscribe and save holders
• Past product viewers

The correct answer is: Past product viewers

Explanation: To help drive purchase goals in Amazon Ads, you should target audiences of past product viewers. These are customers who have previously viewed the detail pages of your advertised products but have not yet purchased. By remarketing to these engaged audiences, you increase the chance of converting their interest into sales—capitalizing on shoppers who have already shown a direct interest in your products. Views remarketing allows you to define lookback windows (such as 7, 14, 30, 60, or 90 days) to focus your campaigns on those most likely to complete a purchase.

Reference: https://advertising.amazon.in/help/G9NXVXPSUB9N6FX5