19. The system of claim 17 , wherein selecting the one or more of the candidate variants as selected variants includes instructions to: sort the candidate variants using the query utility scores to create a ranking; and select the one or more unique queries as selected variants based at least in part on the ranking.
20. The system of claim 19 , wherein selecting the one or more of the candidate variants as selected variants based at least in part on the ranking includes instructions to select a predetermined number of highest ranked candidate variants as a selected variant.