Q63: Are NP-hard problems solvable?

Question 63: Can NP-hard problems never be solved on a computer machine?

1. No, they are unsolvable.
2. They can be solved but they are classified so because they take such a lot of time on current machines that practically computers are useless for all but very small instances of problems.
3. They can be solved but they are classified so because they take such a lot of time on current machines that practically computers are useless for all but very large instances of problems.
4. There are no known solutions for NP-hard problems

Solution: They can be solved but there are no known polynomial time algorithms for them. The correct answer is option 2.