An equilibrium mixture in a vessel of capacity 100 litre contains 1 mol `N_2` , 2mol `O_2` and 3 mol NO. Number of moles of `O_2` to be added so that at new equilibrium the concentration of NO is found to be 0.04 mol/lit :
A. `(101/18)`
B. `(101/9)`
C. `(202/9)`
D. None of these