Then the response will also contain ads for things that are
not the answer to the query. This is how search engines currently behave.
Example from my work. Many of our customers will search for our company name in order to find the login page. I've watched them do this over screen share.
When they do that, the top search result is an ad slot. The second search result is our login page.
We buy ads against out own company name so that we can be the ad slot as well as the first result. Otherwise a competitor who buys ads against our company name could be the top slot.