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_13, if x_13 were a carpenter, then x_13 is a server. For all x_13, x_13 is a carpenter. For all x_13, x_13 is an office clerk or x_13 will listen to a song. For all x_13, if x_13 were an office clerk, then x_13 is a politician. For all x_13, if x_13 listens to a song, then x_13 is a politician.
For all x_13, x_13 is a server can be inferred via the universal modus ponens rule. For all x_13, x_13 is a politician can be inferred via the universal disjunction elimination rule.