In iodometric estimation of `Cu^(2+)` ion, the following reaction took place
`2Cu^(2+)+4ItoCu_(2)I_(2)+I_(2)`
`I_(2)+2Na_(2)S_(2)O_(3)to2NaI+Na_(2)S_(4)O_(6)`
If 100mL OF `CuSO_(4)` solution added to excess KI requires 50mL of 0.2M `Na,S_(2)O_(3)` the molarity of `CuSO_(4)` solution is :
A. `0.05 M`
B. `0.1 M`
C. `0.2 M`
D. `0.25 M`
