The question is incomplete.

1. The prompt says: "In the following reaction 'A' is", but the actual reaction scheme/image is missing.
2. Also, the options A, B, C, D are blank in the text provided.
3. Without the reaction and the answer choices, it is not possible to determine what compound/product/intermediate $A$ is.

So, a chemistry solution cannot be derived from the available information.

What is needed

Please provide at least one of the following:

• the reaction equation/scheme, or
• the image of the question, or
• the full text of options A, B, C, D.

Only then can $A$ be identified and checked against the stored answer D.

Comparison with stored correct answer

Since the problem statement is incomplete, I cannot independently verify whether option D is correct.