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, if x_12 sleeps, then x_12 is playing squash. There is at least one x_12 for which if x_12 drives a car, then x_12 is not a musician. For all x_12, if x_12 plays squash, then x_12 is writing a letter. For all x_12, if x_12 were an electrician, then x_12 is playing squash. For all x_12, x_12 is an electrician or x_12 will sleep. For all x_12, if x_12 writes a letter, then x_12 is a musician.
For all x_12, if x_12 sleeps, then x_12 is writing a letter can be inferred via the universal transitivity rule. For all x_12, if x_12 plays squash, then x_12 is a musician can be inferred via the universal transitivity rule. For all x_12, if x_12 were an electrician, then x_12 is writing a letter can be inferred via the universal transitivity rule. For all x_12, x_12 will play squash can be inferred via the universal disjunction elimination rule.