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_6 for which if x_6 were a taxi driver, then x_6 is working. For all x_6, if x_6 plays tennis, then x_6 is a soldier. For all x_6, if x_6 were a soldier, then x_6 is a taxi driver. For all x_6, if x_6 works, then x_6 is playing tennis.
For all x_6, if x_6 plays tennis, then x_6 is a taxi driver can be inferred via the universal transitivity rule. For all x_6, if x_6 works, then x_6 is a soldier can be inferred via the universal transitivity rule. There is at least one x_6 for which if x_6 were a taxi driver, then x_6 is playing tennis can be inferred via the existential transitivity rule. There is at least one x_6 for which if x_6 were a soldier, then x_6 is working can be inferred via the existential transitivity rule.