5) [1 points] To Prove that " m2=n2 if and only if m=n or m=n ", we need to a) If m2=n2 then m=n or m=n b) If m=n or m=n then m2=n2 c) If m2=n2 then m=n or m=n or If m=n or m=n then m2=n2 d) If m=n and m=n then m2=n2 or If m2=n2 then m=n and m=n e) None of the answers is correct