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: If Barbara drinks water, then Elisabeth is making tea. Susan is an office clerk if and only if Elisabeth is making tea. Susan is not an office clerk.
If Susan were an office clerk, then Elisabeth is making tea can be inferred via the biconditional elimination rule. If Elisabeth makes tea, then Susan is an office clerk can be inferred via the biconditional elimination rule. Elisabeth is not making tea can be inferred via the biconditional elimination rule.