Consider the following premises. For all x_6, if x_6 makes tea, then x_6 is a doctor. For all x_6, if x_6 were a doctor, then x_6 is reading a book. There is at least one x_6 for which if x_6 were happy, then x_6 is making tea. For all x_6, if x_6 were a police officer, then x_6 is happy. Can we infer the following from them? If we can, name the inference rule being used: There is at least one x_6 for which if x_6 were a police officer, then x_6 is reading a book.
 From the fact that for all x_6, if x_6 makes tea, then x_6 is a doctor, and that for all x_6, if x_6 were a doctor, then x_6 is reading a book we can infer that for all x_6, if x_6 makes tea, then x_6 is reading a book via universal transitivity. From the fact that for all x_6, if x_6 were a police officer, then x_6 is happy, and that there is at least one x_6 for which if x_6 were happy, then x_6 is making tea we can infer that there is at least one x_6 for which if x_6 were a police officer, then x_6 is making tea via existential transitivity. Finally, from the fact that there is at least one x_6 for which if x_6 were a police officer, then x_6 is making tea, and that for all x_6, if x_6 makes tea, then x_6 is reading a book we can infer that there is at least one x_6 for which if x_6 were a police officer, then x_6 is reading a book via existential transitivity. Therefore, the answer is yes.