The question asks for the major final product $A$ in a reaction, but the actual reaction scheme/image is missing from the prompt. Also, the options A, B, C, D are blank, so there is no chemical information available to evaluate.

Because of that, the product cannot be determined from the provided text alone.

What is missing?

To solve this, I would need at least one of the following:

1. The full reaction sequence/reagents/substrate, or
2. The reaction image, or
3. The structures corresponding to options $A, B, C, D$.

Conclusion

Since the reaction details are absent, it is not possible to derive the major product.

Therefore, I cannot genuinely verify whether the stored correct answer $A$ is right based on the supplied information.