4. Let be the knowledge base in propositional logic that includes the following propositions: P1, P2, P3, P4, P5, P2^P4 ⇒L, P1 ^P3 ⇒M L^P2^P3⇒Q, L^M⇒R, M^Q^R⇒ T A) Prove that

the above knowledge base covers proposition T using the method of forward execution chaining. B) Prove that the above knowledge base covers proposition T using the method of backward chaining.