The Mole Fraction of Argon in Dry Air near Sea

The mole fraction of argon in dry air near sea level is 1.818 × 10⁵ ,where the molar mass of argon is 39.948.The concentration of argon in the atmosphere is ________ ppm.

A) 9.3 × 10^-9
B) 0.93
C) 9.3 × 10⁶
D) 1.1 × 10⁸
E) 18.18