The question refers to “the following reaction,” but the actual reaction scheme/structure is missing from the prompt. Without the substrate, reagent, or product framework, the number of optically active compounds cannot be determined uniquely.

What is needed

To count the total number of optically active compounds formed, we must know:

1. The starting compound,
2. The reagent/conditions,
3. The possible stereocentres generated or destroyed.

Only then can we determine:

• how many stereoisomeric products form,
• which are chiral,
• whether any meso form exists,
• and hence the number of optically active compounds.

About the stored answer

The stored correct answer is B: Four. Since the reaction image/scheme is absent, I cannot verify this from chemistry reasoning based on the provided data alone.

So, strictly speaking, the problem is incomplete in the current form.