Here's a problem to solve: Which of these would be the best representation of the particles in a solid material?

Among the 4 following options, which is the correct answer?

- A: The football players playing on the field.
 
- B: The planes flying over the football stadium.
 
- C: The spectators sitting in their seats at the football stadium.
 
- D: The spectators arriving at the football stadium and moving to their seats.
 