The root word in the given structure should be hex and alcoholic group forms the suffix and as per the least sum rule of the substituents the position of the substituents that is bromo, chloro and methyl groups should be 1,5 and 4 respectively.
The functional group with highest priority should be getting least possible number in position.
Hence,The correct IUPAC name of the given molecule is 1-bromo-5-chloro-4-methylhexan-3-ol.

