Which of the following statements is logically equivalent to the statement 'All rectangles are polygons'?

ASome rectangles are polygons

BNo rectangles are non-polygons ✓ Correct

CNo non-rectangles are non-polygons

DAll non-polygons are rectangles

Correct answer: (B) No rectangles are non-polygons

Explanation

The equivalent is 'No rectangles are non-polygons'.

The given statement is an A proposition, all S are P.

Obversion changes the quality and replaces the predicate with its complement.

'All rectangles are polygons' obverts to 'no rectangles are non-polygons'.

Obversion is a valid immediate inference that preserves truth-value.

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