Mean Free Path: What Is the Mean Free Path for the Molecules

Mean free path: What is the mean free path for the molecules in an ideal gas when the pressure is 100 kPa and the temperature is 300 K given that the collision cross-section for the molecules of that gas is 2.0 × 10^-20 m²? The Boltzmann constant is 1.38 × 10^-23 J/K, Avogadro's number is 6.02 × 10²³ molecules/mole, and the ideal gas constant is R = 8.314 J/mol ∙ K = 0.0821 L ∙ atm/mol ∙ K.

A) 1.1 × 10^-6 m
B) 2.1 × 10^-6 m
C) 1.7 × 10^-6 m
D) 5.3 × 10^-6 m
E) 1.5 × 10^-6 m