What Is the Average Distance Between Air Molecules at STP $\times$

Multiple Choice

What is the average distance between air molecules at STP?

A) 3.34 $\times$ 10^-17
B) 5.67 $\times$ 10^-17
C) 3.85 $\times$ 10^-17
D) 4.33 $\times$ 10^-17