The correct options are
B Sugar cubes in tea
C Potassium permanganate in water
Diffusion is the movement of particles from an area of high concentration to an area of low concentration.
When a few crystals of potassium permanganate are added to water, the colour of the solution changes. This happens because the solid potassium permanganate particles diffuse into the water.
Similarly, sugar cubes get diffused throughout tea making it sweet.
Ink diffusing in water is an example of liquid in liquid diffusion.
Perfume particles diffusing in the air is an example of liquid in gas diffusion.