The question refers to "A formed in the above reaction", but the actual reaction scheme/image is missing from the prompt. Also, the options A, B, C, D are blank.

Because of this, the compound $A$ cannot be determined from the given text alone.

What is missing

To solve such a question, I would need at least one of the following:

1. The complete reaction equation or scheme.
2. The structures shown in options $A, B, C, D$.
3. The image referred to by "above reaction".

Conclusion

With the current information, the answer cannot be derived logically.

However, the stored correct answer is given as A. Since the actual chemistry content is missing, I cannot independently verify whether option $A$ is truly correct.