Consider the following premises. Jennifer is a police officer. For all x_11, x_11 is excited or x_11 is not a police officer. Can we infer the following from them? If we can, name the inference rule being used: There is at least one x_11 for which x_11 is excited.
 From the fact that for all x_11, x_11 is excited or x_11 is not a police officer we can infer that for all x_11, if x_11 were a police officer, then x_11 is excited via universal rewriting. From the fact that Jennifer is a police officer we can infer that there is at least one x_11 for which x_11 is a police officer via existential generalization. Finally, from the fact that for all x_11, if x_11 were a police officer, then x_11 is excited, and that there is at least one x_11 for which x_11 is a police officer we can infer that there is at least one x_11 for which x_11 is excited via existential modus ponens. Therefore, the answer is yes.