Here's a problem to solve: A teacher opens a can of food in the front of a classroom. Soon, all of the students in the classroom can smell the food. Which statement identifies a property of a gas that allows all of the students to smell the food?

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

- A: A gas has no mass.
 
- B: A gas has a large mass.
 
- C: A gas takes the shape of its container.
 
- D: A gas keeps its shape when placed in a container.
 