Which of the following is tautology
(1) ~(p ∨ ~q) → (p ∨ q)
(2) (~p ∨ q) → (p ∨ q)
(3) ~(p ∧ ~q) → (p ∨ q)
(4) ~(p ∨ ~q) → (p ∧ q)
Answer is (1) ~(p ∨ ~q)→(p ∨ q)
