What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all x_10, x_10 is not sad. There is at least one x_10 for which x_10 will climb a mountain or x_10 will write a letter. For all x_10, if x_10 climbs a mountain, then x_10 is sad.
For all x_10, x_10 will not climb a mountain.