Which of the following is NOT a dicarboxylic acid (a monocarboxylic acid among diacids)

The same question, asked 2 times: 16 May 2023 S1*, 14 May 2024 S2. Every wording below, oldest first.

Try each one first, then open its answer.

Question 1
16 May 2023 S1
80 $Which among the following is NOT dicarboxylic acid?$
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Question 2
14 May 2024 S2
91 $Which among the following is NOT dicarboxylic acid?$
Tap an option to check your answer.