The question refers to "the following reaction" and asks for the final major product, but the actual reaction scheme/structure and the option structures A–D are missing from the prompt.

So, the problem cannot be solved from the given text alone.

Why it cannot be determined

To identify the final major product in organic chemistry, I need:

1. The starting compound(s)
2. The reagents/conditions
3. The structures corresponding to options A, B, C, D

Here, all of these are absent. Therefore, no valid mechanistic analysis can be performed.

Conclusion

Because the reaction and options are not shown, I cannot independently derive the answer. Although the stored correct answer is given as B, I cannot verify it from the available information.