A mixture containing four different colourless amino acids is separated using paper chromatography. The resulting chromatogram is shown. Why are only three spots visible on the chromatogram?
- AA locating agent is not used.
- BOne of the amino acids is insoluble in the solvent.
- CThe solvent front is too near the top of the paper.
- DTwo of the amino acids have the same $R_f$ value.