What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? Charles is not an astronaut or it is cold. It is snowing or Charles is not a mechanic. For all x_16, x_16 is an astronaut or x_16 is a mechanic. It is snowing if and only if it is cold.
If Charles were a mechanic, then it is snowing. If it snows, then it is cold. If it is cold, then it is snowing.