Doubt from reaction with NaBD4

#1

How to solve 36 ? And what is the reaction ?

#2

I think Option A is the answer

#3

Answer is (b)
Even I got option (a).

#4

The reaction(Hydroboration-Oxidation) follows anti-markovnikov mechanism. So -OH group will be attached to less substituted carbon atom. Thus option -b will be correct.