What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? Name the inference rule being used: For all x_7, x_7 will drink water if and only if x_7 is a server. There is at least one x_7 for which x_7 will play squash if and only if x_7 is an office clerk. For all x_7, x_7 will not drink water. For all x_7, x_7 is a server if and only if x_7 will play squash.
For all x_7, if x_7 drinks water, then x_7 is a server can be inferred via the universal biconditional elimination rule. For all x_7, if x_7 were a server, then x_7 is playing squash can be inferred via the universal biconditional elimination rule. There is at least one x_7 for which if x_7 plays squash, then x_7 is an office clerk can be inferred via the existential biconditional elimination rule. For all x_7, if x_7 were a server, then x_7 is drinking water can be inferred via the universal biconditional elimination rule. For all x_7, if x_7 plays squash, then x_7 is a server can be inferred via the universal biconditional elimination rule. There is at least one x_7 for which if x_7 were an office clerk, then x_7 is playing squash can be inferred via the existential biconditional elimination rule. For all x_7, x_7 is not a server can be inferred via the universal biconditional elimination rule.