In order to assess these masses, one must convert all the masses to a single a unit so that they can easily be compared...
3.5 kg = 3.5 kg
350 g = 0.35 kg
3.5 × 10³ hg = 3500 hg = 350 kg
3.5 x 10⁴ cg = 35000 cg = 0.35 kg
∴ 3.5 × 10³ hg is the largest mass.