What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all x_20, x_20 is an astronaut. For all x_20, x_20 will listen to a song or x_20 is not curious. There is at least one x_20 for which if x_20 listens to a song, then x_20 is a politician. For all x_20, x_20 is curious or x_20 is a nurse. For all x_20, x_20 is a nurse if and only if x_20 will listen to a song.
For all x_20, if x_20 were curious, then x_20 is listening to a song. For all x_20, if x_20 were a nurse, then x_20 is listening to a song. For all x_20, if x_20 listens to a song, then x_20 is a nurse.