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: If Elisabeth writes a letter, then Elisabeth is climbing a mountain. For all x_7, x_7 will write a letter or x_7 will not climb a mountain.
For all x_7, if x_7 climbs a mountain, then x_7 is writing a letter can be inferred via the universal rewriting rule.