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_6, if x_6 were a carpenter, then x_6 is a sailor. For all x_6, x_6 will play squash if and only if x_6 is a sailor. For all x_6, x_6 is not an office clerk or x_6 is a carpenter. There is at least one x_6 for which x_6 is an office clerk or x_6 will play squash.
There is at least one x_6 for which x_6 will play squash or x_6 is a carpenter can be inferred via the existential resolution rule. For all x_6, if x_6 plays squash, then x_6 is a sailor can be inferred via the universal biconditional elimination rule. For all x_6, if x_6 were a sailor, then x_6 is playing squash can be inferred via the universal biconditional elimination rule.