The question asks for the total number of stereoisomers for M, but the actual structure/formula of M is missing from the prompt.

Without the structure of M, it is impossible to determine:

1. the number of chiral centers,
2. the presence of geometrical isomerism,
3. any meso form or symmetry,
4. restricted rotation or other stereochemical features.

So the stereoisomer count cannot be derived from the given information alone.

However, the stored correct answer is 2, which suggests that in the original question, compound M likely had exactly one stereogenic element (for example, one chiral center or one $E/Z$ double bond), giving:

$\text{Number of stereoisomers} = 2$

But since the structure is absent, this cannot be independently verified step-by-step.