Still advertisers. It's a nuanced but important difference.
Case A - if you type in "Car" we show an ad about cars. Advertisers are paying to appear at the top of that page. They do not know who you are or what you previously searched.
Case B - if you type in "Car" you are shown an ad about cars. Advertisers are paying to target based on your interest in cars, and possibly other websites you've visited, online actions you've taken, re-marketing pixels from third-party websites, or your affinity to other demographic groups.
Case A - if you type in "Car" we show an ad about cars. Advertisers are paying to appear at the top of that page. They do not know who you are or what you previously searched.
Case B - if you type in "Car" you are shown an ad about cars. Advertisers are paying to target based on your interest in cars, and possibly other websites you've visited, online actions you've taken, re-marketing pixels from third-party websites, or your affinity to other demographic groups.
In "Case A" the search page is the product.
In "Case B" you are the product.