Consider the following premises. For all x_6, x_6 is a lawyer. For all x_6, if x_6 were a doctor, then x_6 is not a lawyer. For all x_6, x_6 is sad if and only if x_6 is a doctor. For all x_6, if x_6 makes tea, then x_6 is sad. Can we infer the following from them? If we can, name the inference rule being used: For all x_6, x_6 will not make tea.
 From the fact that for all x_6, if x_6 were a doctor, then x_6 is not a lawyer, and that for all x_6, x_6 is a lawyer we can infer that for all x_6, x_6 is not a doctor via universal modus tollens. From the fact that for all x_6, x_6 is sad if and only if x_6 is a doctor, and that for all x_6, x_6 is not a doctor we can infer that for all x_6, x_6 is not sad via universal biconditional elimination. Finally, from the fact that for all x_6, if x_6 makes tea, then x_6 is sad, and that for all x_6, x_6 is not sad we can infer that for all x_6, x_6 will not make tea via universal modus tollens. Therefore, the answer is yes.