What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all x_6, x_6 is a writer or x_6 is happy. For all x_6, x_6 is a janitor. For all x_6, if x_6 were a writer, then x_6 is a nurse. There is at least one x_6 for which if x_6 were a janitor, then x_6 is an office clerk. For all x_6, if x_6 were happy, then x_6 is a nurse.
There is at least one x_6 for which x_6 is an office clerk. For all x_6, x_6 is a nurse.