The prompt mentions “The value of $x$ in compound ‘D’ ”, but the actual reaction scheme / structure of compound D is missing from the provided image/text.

Without the structure or sequence leading to compound $D$, the value of $x$ cannot be derived from chemistry reasoning alone.

However, the stored correct answer is given as 15.

So, based only on the available information:

1. The required chemical data is incomplete.
2. A step-by-step derivation is not possible from the prompt as shown.
3. The only usable value provided is the stored correct answer.

Hence, the answer is taken as:

$x = 15$