What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all x_11, x_11 will read a book if and only if x_11 will listen to a song. For all x_11, x_11 will take a plane if and only if x_11 will listen to a song. For all x_11, x_11 will take a plane or x_11 will read a book.
For all x_11, if x_11 reads a book, then x_11 is listening to a song. For all x_11, if x_11 takes a plane, then x_11 is listening to a song. For all x_11, if x_11 listens to a song, then x_11 is reading a book. For all x_11, if x_11 listens to a song, then x_11 is taking a plane.