A student investigated a dye mixture, M\text{M}M, and four reference dyes, W\text{W}W, X\text{X}X, Y\text{Y}Y, and Z\text{Z}Z, using paper chromatography.
The resulting chromatogram is shown below:

Which of the four reference dyes is present in mixture M\text{M}M?
Calculate the RfR_{\text{f}}Rf value of this reference dye using the equation:
Rf=distance moved by dyedistance moved by solventR_{\text{f}} = \frac{\text{distance moved by dye}}{\text{distance moved by solvent}}Rf=distance moved by solventdistance moved by dye