Final answer:
The sample with the greatest entropy is gas vapor. Entropy increases as a substance changes from solid to liquid to gas due to increasing freedom of motion and more possible arrangements of particles.
Step-by-step explanation:
The sample with the greatest entropy is C) Gas vapor.
Entropy is a measure of the disorder or randomness in a system. As a substance changes from solid to liquid to gas, its entropy increases. This is because the particles in a gas have the most freedom of motion, resulting in more possible arrangements of particles and higher entropy. In contrast, a solid has a highly ordered structure and fewer possible arrangements, leading to lower entropy.