The correct option is C 8
All sides are painted of this box. and this box in divided in 64 equal parts.
so let's take that main box was 4∗4∗4 size.
if we remove the outer layer which means that the painted layer then we will have a cube of 2∗2∗2. So no. of boxes which are not painted=8
Hence, option 'C' is correct.