What type of relationship does Charles's law illustrate?

Charles's law describes the relationship between the volume and temperature of a gas at constant pressure. Specifically, it states that when the temperature of a gas increases, its volume also increases, provided the pressure remains constant. This is a direct relationship, meaning that both variables change in the same direction: as one increases, the other increases as well.

To put it in more practical terms, if you take a balloon and heat the air inside it, the air's temperature rises, causing the gas molecules to move faster and spread apart, which results in an increase in the volume of the balloon. This illustrates the core concept of Charles's law. Thus, option B accurately reflects this direct relationship between temperature and volume.