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 z, z will write a letter if and only if z will listen to a song. Karen is not listening to a song. Karen is writing a letter if and only if it is windy. It is windy if and only if Elisabeth is reading a book.
If Karen writes a letter, then it is windy can be inferred via the biconditional elimination rule. If it is windy, then Elisabeth is reading a book can be inferred via the biconditional elimination rule. If it is windy, then Karen is writing a letter can be inferred via the biconditional elimination rule. If Elisabeth reads a book, then it is windy can be inferred via the biconditional elimination rule. For all z, if z writes a letter, then z is listening to a song can be inferred via the universal biconditional elimination rule. For all z, if z listens to a song, then z is writing a letter can be inferred via the universal biconditional elimination rule.