The Mole Fraction of Nitrous Oxide in Dry Air near Sea

The mole fraction of nitrous oxide in dry air near sea level is 1.818 ×
,where the molar mass of nitrous oxide is 44.013.The concentration of nitrous oxide in the atmosphere is ________ ppm.

A) 2.0 × 10¹²
B) 5.0 × 10^-5
C) 500
D) 18.18
E) 5.0 × 10^-13