By which process does the smell of cooking spread to all the rooms in a house?

By which process does the smell of cooking spread to all the rooms in a house?A. Distillation
B. Diffusion
C. Decomposition
D. Displacement

If someone is cooking in the kitchen, the smell travels around the house to other rooms. This is because of diffusion , the movement of particles from an area of high concentration to an area of low concentration.