A $5.52\mathrm{kg}$ sample of bauxite contains $75.0\%$ $\mathrm{Al}{}_2\mathrm{O}{}_3\cdot 2\mathrm{H}{}_2\mathrm{O}$ by mass (molar mass 138) and the rest is inert. It is digested as $\mathrm{Al}{}_2\mathrm{O}{}_3+2\mathrm{NaOH}+3\mathrm{H}{}_2\mathrm{O}\to 2\mathrm{Na}[\mathrm{Al}(\mathrm{OH}){}_4]$ (water of hydration counted among the water). $80.0\%$ of the aluminium is then precipitated as $\mathrm{Al}(\mathrm{OH}){}_3$, which is ignited by $2\mathrm{Al}(\mathrm{OH}){}_3\to \mathrm{Al}{}_2\mathrm{O}{}_3+3\mathrm{H}{}_2\mathrm{O}$. With $\mathrm{Na}=23$, $\mathrm{O}=16$, $\mathrm{H}=1$, $\mathrm{Al}=27$, the mass of NaOH consumed in the digestion and the mass of alumina obtained on ignition are

1. A1.20 kg and 1.96 kg
2. B2.40 kg and 2.45 kg
3. C4.80 kg and 2.45 kg
4. D2.40 kg and 3.06 kg