selection
The rule used to rank candidates and to pick the winner. Null (the default) uses FeasibilityFirstComparator at recommendationCILevel, which is what the solvers themselves use, so confirmation and search agree about what "best" means.
Supplied so that selection policy can be treated as a study-level variable — a benchmark can run the same search under two rules and report the difference — rather than something only a library change can vary.