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_11, if x_11 were a mechanic, then x_11 is playing tennis. There is at least one x_11 for which if x_11 plays tennis, then x_11 is driving a car. For all x_11, x_11 is not a mechanic. For all x_11, x_11 will play tennis if and only if x_11 will drive a car. For all x_11, if x_11 plays tennis, then x_11 is a mechanic.
For all x_11, x_11 will not play tennis can be inferred via the universal modus tollens rule. There is at least one x_11 for which if x_11 were a mechanic, then x_11 is driving a car can be inferred via the existential transitivity rule. For all x_11, x_11 is a mechanic if and only if x_11 will play tennis can be inferred via the universal biconditional introduction rule. For all x_11, x_11 will play tennis if and only if x_11 is a mechanic can be inferred via the universal biconditional introduction rule. For all x_11, if x_11 plays tennis, then x_11 is driving a car can be inferred via the universal biconditional elimination rule. For all x_11, if x_11 drives a car, then x_11 is playing tennis can be inferred via the universal biconditional elimination rule.