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Consider the decision problem 2CNFSAT defined as follows: { Φ | Φ is a satisfiable propositional formula in CNF with at most two literals per clause } For example, Φ = (x1 ∨ x2) ∧ (x1 ∨ x̄3) ∧ (x2 ∨ x4) is a Boolean formula and it is in 2CNFSAT. The decision problem 2CNFSAT is

1. NP-Complete.
2. solvable in polynomial time by reduction to directed graph reachability.
3. solvable in constant time since any input instance is satisfiable.
4. NP-hard, but not NP-complete.

Correct answer: solvable in polynomial time by reduction to directed graph reachability.

Solution

The correct option is right because 2CNFSAT can be transformed into a directed graph problem where the satisfiability of the formula corresponds to finding a path in the graph, allowing it to be solved efficiently in polynomial time.

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