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_6, x_6 is an electrician or x_6 will not write a letter. For all x_6, if x_6 were rich, then x_6 is making tea. For all x_6, if x_6 makes tea, then x_6 is writing a letter.
For all x_6, if x_6 were rich, then x_6 is writing a letter can be inferred via the universal transitivity rule. For all x_6, if x_6 writes a letter, then x_6 is an electrician can be inferred via the universal rewriting rule.