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_12, if x_12 were an office clerk, then x_12 is climbing a mountain. For all x_12, x_12 will drink water and x_12 will listen to a song. There is at least one x_12 for which x_12 is an office clerk.
There is at least one x_12 for which x_12 will climb a mountain can be inferred via the existential modus ponens rule. For all x_12, x_12 will drink water can be inferred via the universal simplification rule. For all x_12, x_12 will listen to a song can be inferred via the universal simplification rule.