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_17 for which x_17 will not take a plane. For all x_17, if x_17 were poor, then x_17 is working. For all x_17, if x_17 were a musician, then x_17 is poor. For all x_17, if x_17 were poor, then x_17 is a musician. For all x_17, if x_17 works, then x_17 is taking a plane.
There is at least one x_17 for which x_17 will not work can be inferred via the existential modus tollens rule. For all x_17, if x_17 were poor, then x_17 is taking a plane can be inferred via the universal transitivity rule. For all x_17, if x_17 were a musician, then x_17 is working can be inferred via the universal transitivity rule. For all x_17, x_17 is a musician if and only if x_17 is poor can be inferred via the universal biconditional introduction rule. For all x_17, x_17 is poor if and only if x_17 is a musician can be inferred via the universal biconditional introduction rule.