When targeting by individual product, which filter would Liu adjust if they want to target a complementary product to the one in their ad?

The correct answer is "Filter by 'expanded'" because this filter allows Liu to target a broader set of complementary products that are related to the product in their ad. The "expanded" filter includes a wider range of products that could be relevant, such as items that frequently appear in the same shopping sessions or that customers often purchase together. This helps Liu reach a larger audience by targeting products that complement the main product in the ad, increasing the likelihood of cross-selling. In contrast, the "exact" filter is used to target specific products or keywords, and the "category" filter targets broader product categories, neither of which would specifically target complementary products as effectively as the "expanded" filter.