What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all x, if x writes a letter, then x is a writer. For all x, if x drives a car, then x is writing a letter. For all x, if x writes a letter, then x is driving a car. There is at least one x for which if x were a writer, then x is writing a letter. For all x, x will drive a car or x is a writer.
For all x, if x drives a car, then x is a writer. There is at least one x for which if x were a writer, then x is driving a car. There is at least one x for which x will write a letter. For all x, x will drive a car if and only if x will write a letter. For all x, x will write a letter if and only if x will drive a car. There is at least one x for which x is a writer if and only if x will write a letter. There is at least one x for which x will write a letter if and only if x is a writer.