Which of the following statements are so related that one is the denial or the negation of the other?

1.All aeroplanes are polluting vehicles

2.No aeroplanes are polluting vehicles

3.Some aeroplanes are polluting vehicles

4.Some aeroplanes are not polluting vehicles

A3 & 4 only

B2 & 4 only

C1 & 4 only ✓ Correct

D1 & 2 only

Correct answer: (C) 1 & 4 only

Explanation

Statements 1 and 4 are the denial of each other.

Statement 1 "All aeroplanes are polluting vehicles" is an A proposition.

Statement 4 "Some aeroplanes are not polluting vehicles" is its O proposition.

A and O are contradictories on the square of opposition.

Contradictories always take opposite truth-values, so each negates the other.

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