A solution containing $2.675\; g$ of $CoCl_3. 6 NH_3$ (molar mass =$267.5 \;g \;mol^{–1})$ is passed through a cation exchanger. The chloride ions obtained in solution were treated with excess of $AgNO_3$ to give $4.78\; g$ of $AgCl$ (molar mass $= 143.5\; g \;mol^{–1}$). The formula of the complex is (At. Mass of $Ag = 108 \;u$)

Question

( A ) $[Co(NH_3)_6]Cl_3$
( B ) $[CoCl_2(NH_3)_4]Cl$
( C ) $[CoCl(NH_3)_5]Cl_2$
( D ) $[CoCl_3(NH_3)_3]$