The question asks for the main reduction product with $NaBH_4$ in methanol, but the actual structure of the starting compound and the option structures A–D are missing from the prompt.

So, a definite product cannot be derived from the given information alone.

Step-by-step reasoning

1. Role of $NaBH_4$ in methanol

   Sodium borohydride is a mild reducing agent. In methanol, it commonly reduces:

   • aldehydes $\rightarrow$ primary alcohols
   • ketones $\rightarrow$ secondary alcohols

2. What it usually does not reduce under ordinary conditions

   $NaBH_4$ generally does not reduce:

   • carboxylic acids
   • esters
   • amides
   • most isolated $C=C$ bonds

3. Why the answer cannot be fixed here

   Since the image/structure of the compound is absent, I cannot determine:

   • which functional group is present,
   • whether there are competing reducible groups,
   • what the stereochemical outcome is,
   • which option corresponds to the actual product.

4. About the stored answer

   The stored correct answer is given as B, but without the compound and option structures, there is no way to independently verify that choice.

Conclusion

A conclusive solution is not possible from the incomplete question data. If you provide the structure/image, I can determine the exact product and verify whether B is correct.