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_10, x_10 will listen to a song if and only if x_10 is happy. For all x_10, x_10 will listen to a song if and only if x_10 is happy.
For all x_10, if x_10 listens to a song, then x_10 is happy can be inferred via the universal biconditional elimination rule. For all x_10, if x_10 listens to a song, then x_10 is happy can be inferred via the universal biconditional elimination rule. For all x_10, if x_10 were happy, then x_10 is listening to a song can be inferred via the universal biconditional elimination rule. For all x_10, if x_10 were happy, then x_10 is listening to a song can be inferred via the universal biconditional elimination rule.