Answer : (4) Chromatography
Explanation :
Chromatography : It is a separation technique of a mixture by passing it through a medium in which components travels at different rates.
There are many types of chromatography but this is paper chromatography.
Paper chromatography : It is used to separate the colored substances. In paper chromatography, water is the mobile phase and paper is the stationary phase. The mixture of components moves at different speeds through the stationary phase so that they can be separated.
In paper chromatography, several colors can be separated based on their solubility. The more soluble a color is, the more readily it will dissolve in mobile phase and farther it will travel.