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_3, x_3 will read a book if and only if x_3 is bored. For all x_3, x_3 will not write a letter or x_3 will make tea. For all x_3, x_3 is not bored. There is at least one x_3 for which x_3 will write a letter or x_3 will read a book.
There is at least one x_3 for which x_3 will read a book or x_3 will make tea can be inferred via the existential resolution rule. For all x_3, if x_3 reads a book, then x_3 is bored can be inferred via the universal biconditional elimination rule. For all x_3, if x_3 were bored, then x_3 is reading a book can be inferred via the universal biconditional elimination rule. For all x_3, x_3 will not read a book can be inferred via the universal biconditional elimination rule.