Here's a problem to solve: A class is modeling the differences between a unicellular organism and a multicellular organism. Which example is a model of a unicellular organism?

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

- A: a student passing out water to a group
 
- B: a student getting cereal from the cabinet
 
- C: two students collecting trash from a group
 
- D: four students working together to move a desk
 