(8 points) Choose either True, False, or Unknown for each of the following statements. (a) There is an NP-complete problem that is polynomial-time solvable. True False Unknown (b) All NP-complete problems are poly-time solvable. True False Unkown (c) Some NP-complete problems are poly-time solvable and some NP-complete problems are not polytime solvable True False Unkown (d) There is no NP-complete problem that can be solved in polynomial-time. True False Unkown