Which of the following statements are logically equivalent? Choose the correct answer from the options given below:

1.All integers are real numbers.

2.All non-integers are non-real numbers.

3.All real numbers are integers.

4.No integers are non-real numbers.

A1, 2 & 3 only

B3 & 4 only

C2 & 4 only

D1 & 4 only ✓ Correct

Correct answer: (D) 1 & 4 only

Explanation

Statements 1 (All integers are real numbers) and 4 (No integers are non-real numbers) are logically equivalent.

Statement 1 is a universal affirmative of the form all I are R.

Its obverse replaces the predicate by its complement and changes quality, giving no I are non-R.

That obverse is exactly Statement 4, and obversion always preserves logical equivalence.

Their identity rests on obversion, a truth-preserving immediate inference.

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