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 read a book or x_10 will play squash. For all x_10, if x_10 reads a book, then x_10 is making tea. There is at least one x_10 for which if x_10 makes tea, then x_10 is reading a book. For all x_10, x_10 will not make tea.
For all x_10, x_10 will not read a book can be inferred via the universal modus tollens rule. There is at least one x_10 for which x_10 will make tea if and only if x_10 will read a book can be inferred via the existential biconditional introduction rule. There is at least one x_10 for which x_10 will read a book if and only if x_10 will make tea can be inferred via the existential biconditional introduction rule.