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_12, x_12 will write a letter and x_12 is a politician. There is at least one x_12 for which x_12 will not work. For all x_12, x_12 will work or x_12 is a taxi driver.
There is at least one x_12 for which x_12 is a taxi driver can be inferred via the existential disjunctive syllogism rule. For all x_12, x_12 will write a letter can be inferred via the universal simplification rule. For all x_12, x_12 is a politician can be inferred via the universal simplification rule.