What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? Name the inference rule being used: Susan is a writer or it is not sunny. It is sunny if and only if Susan is a writer. If it is sunny, then Susan is a writer.
If it is sunny, then Susan is a writer can be inferred via the rewriting rule. If it is sunny, then Susan is a writer can be inferred via the biconditional elimination rule. If Susan were a writer, then it is sunny can be inferred via the biconditional elimination rule.