From the following, identify the propositions that are logically equivalent. Choose the correct answer from the options given below.

1.No plants are animals

2.No animals are plants

3.All plants are non-animals

4.All non-animals are plants

A1 and 4 only

B2 and 3 only

C1, 2 and 3 only ✓ Correct

D1 and 3 only

Correct answer: (C) 1, 2 and 3 only

Explanation

Statements 1, 2 and 3 all express the same denial of overlap between plants and animals.

Statement 1 is 'No plants are animals', a universal negative.

Statement 2, 'No animals are plants', is its simple converse.

Statement 3, 'All plants are non-animals', is its obverse.

Conversion and obversion of the E form both preserve the truth value.

So the three are logically equivalent, while 'All non-animals are plants' is not.

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