When altitude of earth is in between 90 km and 150 km Knudsen number can be in between 0.3 and _________

When altitude of earth is in between 90 km and 150 km Knudsen number c

1.	When altitude of earth is in between 90 km and 150 km Knudsen number can be in between 0.3 and _________
A.	1
B.	2
C.	3
D.	4
Answer» B. 2