Answer
(a)
Work Step by Step
The first diagram shows a mixture of two different gaseous components. Because each gas is represented by a sphere of a distinct hue, we can tell that there are two gases present. Because they are floating freely, as gas particles do, we can be certain that these atoms are in the gaseous state.
The red spheres that are arranged rigidly in the second diagram indicate the other gas, which has condensed, while one of the two gaseous elements in the first diagram is still in a gaseous condition.
Option (a) is appropriate for this situation.
