What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all x_11, x_11 is happy if and only if x_11 is a nurse. For all x_11, x_11 is happy if and only if x_11 is a nurse.
For all x_11, if x_11 were happy, then x_11 is a nurse. For all x_11, if x_11 were happy, then x_11 is a nurse. For all x_11, if x_11 were a nurse, then x_11 is happy. For all x_11, if x_11 were a nurse, then x_11 is happy.