On treatment of $100 \;mL$ of $ 0.1 \;M$ solution of $CoCl_3.6H_2O$ with excess $AgNO_3;\; 1.2 \times 10^{22}$ ions are precipitated. The complex is :

Question

( A ) $[Co(H_2O)_4Cl_2]Cl.2H_2O$
( B ) $[Co(H_2O)_6]Cl_3$
( C ) $[Co(H_2O)_3Cl_3].3H_2O$
( D ) $[Co(H_2O)_5Cl]Cl_2.H_2O$