What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all x_12, if x_12 were a scientist, then x_12 is a police officer. For all x_12, if x_12 were a police officer, then x_12 is a scientist. It is overcast. Barbara is not a police officer.
It is overcast and Barbara is not a police officer. Barbara is not a police officer and it is overcast. For all x_12, x_12 is a scientist if and only if x_12 is a police officer. For all x_12, x_12 is a police officer if and only if x_12 is a scientist.