The chromatogram for mixture X and the pure substances P, Q, R and S is shown. Which of the following statements is correct?
- AR is completely insoluble in the solvent used.
- BThe $R_f$ value of Q is greater than the $R_f$ value of S.
- CX is a mixture of Q, R and S.
- DThe paper is placed in the solvent with the solvent above the baseline.