Problems P1 and P2 are unknown decision problems (i.e., don't have information about P or NP). If any of one NP-Complete problem (let say SAT) is the polynomial-time reducible to P1, and P2 is reducible to a one problem present in NP, and that problem is again reducible to NP-Complete problem in polynomial time, then P1 and P2 will become which class? Justify your answer with a proper explanation? How Polynomial time Reduction (reducibility) useful to prove P=NP or P! = NP