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: For all x_12, x_12 will take a plane if and only if x_12 is a musician. For all x_12, if x_12 were a musician, then x_12 is taking a plane. For all x_12, x_12 will take a plane if and only if x_12 is curious. There is at least one x_12 for which x_12 is not curious.
For all x_12, if x_12 takes a plane, then x_12 is a musician can be inferred via the universal biconditional elimination rule. For all x_12, if x_12 takes a plane, then x_12 is curious can be inferred via the universal biconditional elimination rule. For all x_12, if x_12 were a musician, then x_12 is taking a plane can be inferred via the universal biconditional elimination rule. For all x_12, if x_12 were curious, then x_12 is taking a plane can be inferred via the universal biconditional elimination rule. There is at least one x_12 for which x_12 will not take a plane can be inferred via the existential biconditional elimination rule.