Consider the following premises. For all x_11, x_11 will make tea. For all x_11, if x_11 makes tea, then x_11 is a doctor. For all x_11, x_11 is not sad. There is at least one x_11 for which x_11 is sad if and only if x_11 is a doctor. Can we infer the following from them? If we can, name the inference rule being used: For all x_11, x_11 is not a mechanic.
The premises are contradictory and we can infer anything from them. Therefore, the answer is yes.