Magnesium reduced `NO_(3)` according to the equation given below:
`NO_(3)^(-) + Mg + 3H_(2)O rarr Mg(OH)_(2)+ OH + NH_(3)`
In basic medium, 25 ml sample of `NO_(2)` was reacted with Mg. The ammonia gas evolved was passed through 50 ml of 1.15 N HCI. The excess HCI required 32.1 ml of 0.1 M NaOH for neutralization. The molarity of `NO_(3)` in the original sample is

Options

A. 0.1M
B. 0.171M
C. 0.2M
D. 0.5M