Which of these can undergo decarboxylation reaction readily Which of these carboxylic acids can undergo decarboxylation readily?


According to what I know beta-keto acids undergo decarboxylation easily and readily due to formation of a stable intermediate. So my general answer was option (A) however the answer key states that (A),(B) and (D) are correct. I am not able to understand, based on my current theory what is the reason for (B) and (D) to undergo decarboxylation readily.
You have said that  β−ketoacids undergo decarboxylation easily and readily due to formation of a stable intermediate. That intermediate is the carbanion on the alpha carbon. So, any species that can stabilize that carbanion can undergoe decarboxylation easily. In (B), the carbanion formed is stabilized by the double bond beside it so it undergoes decarboxylation easily.
(D) is a special reaction as referenced to in this answer.