How does the volume of a gas changes when pressure is applied on it?

Gases are highly compressible in nature; thus, the large volume of gas can easily be compressed in a cylinder due to this property.

When the gas particles are compressed closer together as the pressure on a gas rises, the volume of the gas decreases. In contrast, as a gas's pressure falls, its volume rises as a result of the gas's ability to spread its particles farther apart.

Thus, we can say that the volume of gas decreases when compressed by applying pressure.

Hence, the correct option is (B).