A builder wishes to fit 8 different types of electrical bulbs in his flats, which are packed by a vendor in some boxes of count 64, 192, 128, 384, 256, 32, 96, 288. The builder ordered in such away that each box contains the same type and the same number of bulbs. The number of minimum boxes required is:

We should choose a number which is a factor of all of these numbers so that when they are grouped among themselves, there are no leftovers. 
The count in the boxes have HCF 32, so we can distribute the bulbs in groups of 32 so that each box has 32 bulbs and each box has only one type of bulb. 

The bulb with 64 count would require 2 boxes.
The bulb with 192 count would require 6 boxes.
The bulb with 128 count would require 4 boxes.
The bulb with 384 count would require 12 boxes.
The bulb with 256 count would require 8 boxes.
The bulb with 32 count would require 1 boxes.
The bulb with 96 count would require 3 boxes.
The bulb with 288 count would require 9 boxes.

Adding all of them up, we would get that a total of 45 boxes are required. 
Therefore, Option B is the correct answer.