What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all x_15, if x_15 takes a plane, then x_15 is excited. If it is cold, then Robert is not excited. For all x_15, if x_15 were fast, then x_15 is excited. For all x_15, x_15 will not listen to a song or x_15 is fast. For all x_15, x_15 will listen to a song or x_15 will take a plane.
For all x_15, x_15 will take a plane or x_15 is fast.