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 an office clerk. It is snowing if and only if David is fast. It is snowing if and only if Karen is an office clerk.
If it snows, then David is fast. If it snows, then Karen is an office clerk. If David were fast, then it is snowing. If Karen were an office clerk, then it is snowing.