Cho sơ đồ sau Cr(OH)3 tác dụng với Br2 , KOH ra X , x ra Y, Y ra SO2

A. ${\mathrm{K}}_2{\mathrm{Cr}}_2{\mathrm{O}}_7, {\mathrm{K}}_2{\mathrm{Cr}}_2{\mathrm{O}}_4, {\mathrm{Cr}}_2{\left({\mathrm{SO}}_4\right)}_3$

B. ${\mathrm{K}}_2{\mathrm{Cr}}_2{\mathrm{O}}_4, {\mathrm{K}}_2{\mathrm{Cr}}_2{\mathrm{O}}_7, {\mathrm{Cr}}_2{\left({\mathrm{SO}}_4\right)}_3$

C. ${\mathrm{KCrO}}_2, {\mathrm{K}}_2{\mathrm{Cr}}_2{\mathrm{O}}_7, {\mathrm{Cr}}_2{\left({\mathrm{SO}}_4\right)}_3$

D. ${\mathrm{KCrO}}_2, {\mathrm{K}}_2{\mathrm{Cr}}_2{\mathrm{O}}_4, {\mathrm{CrSO}}_4$