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: There is at least one x_5 for which x_5 will climb a mountain. For all x_5, if x_5 climbs a mountain, then x_5 is an astronaut. For all x_5, x_5 will read a book.
There is at least one x_5 for which x_5 is an astronaut can be inferred via the existential modus ponens rule. There is at least one x_5 for which x_5 will climb a mountain and x_5 will read a book can be inferred via the existential conjunction rule. There is at least one x_5 for which x_5 will read a book and x_5 will climb a mountain can be inferred via the existential conjunction rule.