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_11, if x_11 listens to a song, then x_11 is writing a letter. For all x_11, x_11 will listen to a song. There is at least one x_11 for which if x_11 makes tea, then x_11 is bored. For all x_11, if x_11 were bored, then x_11 is writing a letter. For all x_11, if x_11 writes a letter, then x_11 is bored.
For all x_11, x_11 will write a letter can be inferred via the universal modus ponens rule. For all x_11, if x_11 listens to a song, then x_11 is bored can be inferred via the universal transitivity rule. There is at least one x_11 for which if x_11 makes tea, then x_11 is writing a letter can be inferred via the existential transitivity rule. For all x_11, x_11 is bored if and only if x_11 will write a letter can be inferred via the universal biconditional introduction rule. For all x_11, x_11 will write a letter if and only if x_11 is bored can be inferred via the universal biconditional introduction rule.