What conclusion can be drawn from the experiment in which potassium permanganate solution remains coloured even after repeated dilution?

The correct option is: Particles of matter are extremely small in size.

Explanation:
When a few crystals of potassium permanganate (${\mathrm{KMnO}}_4$) are dissolved in water, they impart a deep pink or purple colour to the solution.
If we take a small portion of this coloured solution and dilute it by adding more water, the colour becomes lighter but it still remains colored. Even after repeating this dilution process several times, the colour does not disappear completely.

This observation indicates that just a few crystals of potassium permanganate contain millions of tiny particles. When diluted, these particles keep dividing themselves into smaller and smaller particles, spreading throughout the larger volume of water.
Therefore, this experiment proves that the particles of matter are extremely small in size, beyond our imagination.