I.   Determine whether each argument corresponds to a rule of
            inference, and for each that does, state which rule of
            inference it corresponds to.

           A.   (P v Q) -> (R & S)
                ~(R & S)
                ------------------
                ~(P v Q)

           B.   (P v [{Q v P} -> {R v S}]) & (S -> [R & T])
                -------------------------------------------
                (P v [{Q v P} -> {R v S}])

           C.   ([P & Q] -> R) & (S -> [T v U])
                ~(P & Q) v ~S
                -------------------------------
                ~R v ~(T v U)

           D.   P & Q
                -----------
                P & (Q v R)

           E.   (P -> Q) -> R
                R -> (S v T)
                -------------------
                (P -> Q) -> (S v T)

           F.   (P -> T) & ([R v S] -> T)
                P v (R v S)
                -------------------------
                T v T