What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all x_1, x_1 is a sailor if and only if x_1 will drive a car. Susan is a musician or Barbara is driving a car. If Susan were a musician, then Barbara is a sailor.
If Barbara were happy, then Susan is a musician. For all x_1, if x_1 were a sailor, then x_1 is driving a car. For all x_1, if x_1 drives a car, then x_1 is a sailor.