It's hard to imagine today a search engine that would try to deliver just one correct result instead of ten as they usually do. Namely, not even Google has the skill and technology to deliver the correct result most of the times. But letting a user choose among the ten drastically improves chances of the user to find something click-worthy among the search results, as demonstrated by the following chart
This chart shows the probability (y axis) of finding at least one click-worthy result among n (x axis) results for the case when the probability of individual result to be interesting to the user is 30%. The chart clearly shows that delivering just one result would disappoint the user in seven out of ten cases, while providing ten results decreases chances of completely disappointing the user to just three percent.
Search engines do a tremendous amount of work by combing trillions of documents in their indexes to identify ten potentially suitable results. But still they only do just 30-50% of total work involved in finding the one right answer. The rest is done by us, the users, as we scan the search results page. And that's the hidden genius of search engines in general and Google in particular.