What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? Name the inference rule being used: There is at least one x_10 for which if x_10 plays squash, then x_10 is excited. For all x_10, if x_10 were a sailor, then x_10 is playing squash. For all x_10, x_10 is excited if and only if x_10 is a sailor.
There is at least one x_10 for which if x_10 were a sailor, then x_10 is excited can be inferred via the existential transitivity rule. For all x_10, if x_10 were excited, then x_10 is a sailor can be inferred via the universal biconditional elimination rule. For all x_10, if x_10 were a sailor, then x_10 is excited can be inferred via the universal biconditional elimination rule.