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_8, x_8 is a mechanic and x_8 is rich. For all x_8, if x_8 drinks water, then x_8 is writing a letter. For all x_8, x_8 will drink water.
For all x_8, x_8 will write a letter can be inferred via the universal modus ponens rule. For all x_8, x_8 is a mechanic can be inferred via the universal simplification rule. For all x_8, x_8 is rich can be inferred via the universal simplification rule.