Consider the following premises. There is at least one x_6 for which x_6 is a server. For all x_6, x_6 will sleep or x_6 is not a janitor. For all x_6, x_6 is a janitor. Can we infer the following from them? If we can, name the inference rule being used: For all x_6, x_6 is a janitor.
That is one of the premises. Therefore, the answer is yes.