The question refers to a reaction sequence and asks for the major product $B$, but the actual reaction scheme/structures and option structures are missing in the prompt.

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

What is missing?

To determine product $B$, I need:

1. The starting compound,
2. The reagents/conditions in each step of the sequence,
3. The structures corresponding to options A, B, C, and D.

Without these, there is no chemical basis to derive the product.

Comparison with stored answer

The stored correct answer is given as B, but since the reaction sequence itself is absent, I cannot independently verify whether option B is actually correct.

Therefore, I must disagree with the stored answer for now, because the provided information is insufficient to solve the question rigorously.