Consider the following premises. For all x_20, x_20 is an office clerk if and only if x_20 will cook. If Linda were not an office clerk, then Elisabeth is curious. Linda is not cooking. Karen is a carpenter. Can we infer the following from them? If we can, name the inference rule being used: Karen is a carpenter and Elisabeth is curious.
 From the fact that for all x_20, x_20 is an office clerk if and only if x_20 will cook we can infer that Linda is an office clerk if and only if Linda is cooking via universal instantiation. From the fact that Linda is an office clerk if and only if Linda is cooking, and that Linda is not cooking we can infer that Linda is not an office clerk via biconditional elimination. From the fact that if Linda were not an office clerk, then Elisabeth is curious, and that Linda is not an office clerk we can infer that Elisabeth is curious via modus ponens. Finally, from the fact that Karen is a carpenter, and that Elisabeth is curious we can infer that Karen is a carpenter and Elisabeth is curious via conjunction. Therefore, the answer is yes.