The question as provided is incomplete: the reaction sequence image/scheme is missing, and the options A–D are also blank. Because the actual structures/reagents are not visible, the major products $A$ and $B$ cannot be determined.

Step-by-step assessment

1. To solve a reaction-sequence question in organic chemistry, we need:

   • the starting compound,
   • the reagents/conditions in each step,
   • and the answer options (structures of products).

2. In the current prompt, only the sentence

   “In the following reaction sequence the major products A and B are:” is available, but the actual sequence is absent.

3. Since neither the reaction pathway nor the options are provided, any attempt to choose among $A$, $B$, $C$, or $D$ would be a guess rather than a valid chemical solution.

Conclusion

The problem cannot be solved from the given information. Please provide the reaction scheme/image and the option structures.

Because of the missing data, I cannot honestly verify the stored answer $D$.