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 y_1, if y_1 were a musician, then y_1 is playing tennis. For all y_1, y_1 is not a taxi driver. For all y_1, if y_1 were a mechanic, then y_1 is a musician. For all y_1, y_1 is a taxi driver if and only if y_1 is a musician. For all y_1, y_1 is a mechanic or y_1 will not play tennis.
For all y_1, if y_1 were a mechanic, then y_1 is playing tennis can be inferred via the universal transitivity rule. For all y_1, if y_1 plays tennis, then y_1 is a mechanic can be inferred via the universal rewriting rule. For all y_1, if y_1 were a taxi driver, then y_1 is a musician can be inferred via the universal biconditional elimination rule. For all y_1, if y_1 were a musician, then y_1 is a taxi driver can be inferred via the universal biconditional elimination rule. For all y_1, y_1 is not a musician can be inferred via the universal biconditional elimination rule.