What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all x_6, if x_6 drives a car, then x_6 is not climbing a mountain. For all x_6, x_6 will climb a mountain. For all x_6, x_6 will drive a car if and only if x_6 will write a letter.
For all x_6, x_6 will not drive a car. For all x_6, if x_6 drives a car, then x_6 is writing a letter. For all x_6, if x_6 writes a letter, then x_6 is driving a car.