Which of the following statements about NP-Hard and NP-Complete problems is correct?

Options

  • A. Every NP-Hard problem must belong to NP
  • B. Every NP-Complete problem is NP-Hard
  • C. Every problem in P is NP-Complete
  • D. More than one of the above
  • E. None of the above

Correct Answer (Detailed Explanation is Below)

B. Every NP-Complete problem is NP-Hard

Detailed Explanation

  • NP-Hard: A problem at least as hard as every problem in NP under polynomial-time reductions.
  • NP-Complete: Problems that are both NP-Hard and members of NP.
  • Important Difference: NP-Hard problems need not belong to NP.
  • Exam Shortcut: NP-Complete is a subset of NP-Hard.