Consider the following premises. Susan is not making tea. Karen is not listening to a song. For all x_11, x_11 is a cashier if and only if x_11 will make tea. For all z, z is a doctor if and only if z will listen to a song. Can we infer the following from them? If we can, name the inference rule being used: Susan is not a cashier and Karen is not a doctor.
 From the fact that for all z, z is a doctor if and only if z will listen to a song we can infer that Karen is a doctor if and only if Karen is listening to a song via universal instantiation. From the fact that Karen is a doctor if and only if Karen is listening to a song, and that Karen is not listening to a song we can infer that Karen is not a doctor via biconditional elimination. From the fact that for all x_11, x_11 is a cashier if and only if x_11 will make tea we can infer that Susan is a cashier if and only if Susan is making tea via universal instantiation. From the fact that Susan is a cashier if and only if Susan is making tea, and that Susan is not making tea we can infer that Susan is not a cashier via biconditional elimination. Finally, from the fact that Susan is not a cashier, and that Karen is not a doctor we can infer that Susan is not a cashier and Karen is not a doctor via conjunction. Therefore, the answer is yes.