In a formal proof, what is the 'Modus Ponens' rule?
If P ⟹ QP \implies QP⟹Q and ¬Q\neg Q¬Q, conclude ¬P\neg P¬P.
If P ⟹ QP \implies QP⟹Q and PPP, conclude QQQ.
If P∧QP \land QP∧Q, conclude PPP.
If P∨QP \lor QP∨Q and ¬P\neg P¬P, conclude QQQ.