Which of the following are tautologies?
A. (p ∨ r) → p
B. p → (p ∧ r)
C. ~p → (p → r)
D. (p ∧ r) → (p → r)
E. ~(p → r) → p
Choose the correct answer from the options given below:
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Correct answer: D. C, D, E Only
Explanation
C: if p is false, p → r is true. D: if p ∧ r holds, p → r holds. E: ~(p → r) means p ∧ ~r, which implies p. A and B fail for (p, r) = (F, T) and (T, F).More Discrete Structures and Optimisation questions
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