Orange-red vapours from the chromyl chloride test are passed into aqueous NaOH to give a yellow solution. The solution is acidified with acetic acid and lead acetate solution is added. The yellow precipitate is:

1. A$\mathrm{PbCr}{}_2\mathrm{O}{}_7$
2. B$\mathrm{PbO}{}_2$
3. C$\mathrm{PbCrO}{}_4$
4. D$\mathrm{PbCl}{}_2$