For the purpose of this question, assume it is known that P is not equal to NP, but NP is equal to co-NP. For each problem below, check all and only the classes to which the problem would then be known to belong. (a) 2SAT (given a Boolean expression that is the AND of factors, each factor being the OR of two literals, is this expression satisfiable?): NP CO-NP (b) The Tautology problem (given a Boolean expression, is it true for all possible truth assignments?): OP NP CO-NP (c) The 3-Knapsack problem (given a set of integers, can it be partitioned into THREE disjoint sets such that the sum of the members of each set is the same?): NP CO-NP