The question refers to an "above chemical reaction", asking for intermediate $X$ and reagent/condition $A$, but the actual reaction scheme is missing from the prompt. Also, the options $A, B, C, D$ are blank.

Because of this, there is not enough information to derive the chemical transformation, identify the intermediate, or determine the reagent/condition.

What is missing

1. The reaction scheme containing the compound transformations.
2. The definition of intermediate $X$.
3. The reagent/condition label $A$.
4. The actual option statements for choices $A, B, C, D$.

Therefore

Without the reaction diagram and options, the problem cannot be solved logically from the given data.

Comparison with stored answer

The stored correct answer is given as D, but since the essential reaction information is absent, I cannot independently verify whether option $D$ is correct.

Please provide the full reaction scheme (image or text) and the option contents so I can solve it step-by-step.