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_8, x_8 is curious if and only if x_8 will cook. There is at least one x_8 for which if x_8 were sad, then x_8 is curious. For all x_8, x_8 will cook or x_8 is sad. For all x_8, if x_8 cooks, then x_8 is curious.
There is at least one x_8 for which x_8 is curious can be inferred via the existential disjunction elimination rule. For all x_8, if x_8 were curious, then x_8 is cooking can be inferred via the universal biconditional elimination rule. For all x_8, if x_8 cooks, then x_8 is curious can be inferred via the universal biconditional elimination rule.