What Is the Mean Free Path of Molecules in an Ideal

What is the mean free path of molecules in an ideal gas in which the mean collision time is 3.00 × 10^-10 s,the temperature is 300 K,and the mass of the molecules is 6.00 × 10^-25 kg? Assume that the molecules are moving at their root-mean-square speeds.The Boltzmann constant is 1.38 × 10^-23 J/K.

A) 7.22 × 10^-8 m
B) 4.32 × 10^-8 m
C) 9.19 × 10^-8 m
D) 1.39 × 10^-8 m
E) 6.71 × 10^-8 m