In a flask of volume 'V' litres, 0.2 moles of $$O_2$$. 0.4 moles of $$N_2$$ , 0.1 moles of $$NH_3$$ and 0.3 moles of $$He$$ gases are present at 27 °C. If the total pressure exerted by these non-reacting gases is 1 atm, the partial pressure exerted by $$N_2$$ gas is:

A

0.3 atm

B

0.1 atm

C

0.2 atm

D

0.4 atm