Kilograms to grams; volume

800kgs -> 1 cubic m = 10^6 cubic cm
8 * 10^5 gm = 10^6 cubic cm
or 1 gm = 10/8 = 1.25
IMO B

We can just do a nice straightforward unit conversion to get the answer:

(1 cub meter / 800 kg) * (1 kg / 1000g) * (1,000,000 cub cm / 1 cub meter)

I set it up this way so the kg's and the cubic meters cancel out and we are left with the label the question is asking for: cubic cm/gram.

= 1,000,000 / 800,000

5 zeroes will cancel: 10/8 = 5/4

The answer is B.