Answer:
1) 1m³ is 100cm*100cm*100cm = 1,000,000cm³
so 250,00cm³ are just 0.25m³
2) looking at the conversion above, three point five million is correct
3) 1dm³ = 10cm*10cm*10cm = 1,000cm³
D, as in Dewey Duck
4) 1m³ = 10dm*10dm*10dm = 1,000dm³
see that it's C?
