The question asks for the number of optically active stereoisomers of compound $X$, but the structure of compound $X$ is not shown in the prompt.

Without the actual structure, it is impossible to determine:

1. the number of stereocentres,
2. whether any meso forms exist,
3. whether there are geometrical stereoisomers,
4. and hence the number of optically active stereoisomers.

What would normally be done

If the structure were given, the steps would be:

1. Identify all stereogenic elements

   • chiral centres,
   • double bonds with $E/Z$ isomerism,
   • axial chirality, etc.

2. Calculate total stereoisomers

   • often using $2^n$ for $n$ independent stereocentres,
   • then reduce for symmetry/meso forms if present.

3. Count only optically active ones

   • exclude meso compounds,
   • exclude achiral stereoisomers.

Since structure is missing

A definite answer cannot be derived from the information provided.

However, the stored correct answer is given as $7$. Since I cannot verify it without the structure, I cannot honestly derive the same from first principles.