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_13, if x_13 were excited, then x_13 is curious. For all x_13, if x_13 were happy, then x_13 is an astronaut. For all x_13, x_13 is a taxi driver or x_13 is excited. For all x_13, x_13 will climb a mountain. For all x_13, x_13 is happy. For all x_13, if x_13 were a taxi driver, then x_13 is curious.
For all x_13, x_13 is an astronaut can be inferred via the universal modus ponens rule. For all x_13, x_13 will climb a mountain and x_13 is happy can be inferred via the universal conjunction rule. For all x_13, x_13 is happy and x_13 will climb a mountain can be inferred via the universal conjunction rule. For all x_13, x_13 is curious can be inferred via the universal disjunction elimination rule.