A paper chromatography investigation is carried out to determine an $R_f$ value for $\text{Fe}^{3+}(aq)$. The chromatogram is shown. To make the spot that contains $\text{Fe}^{3+}(aq)$ easier to see, the paper is sprayed with aqueous sodium hydroxide so that iron(III) hydroxide precipitate is produced. In the chromatogram, the $R_f$ of $\text{Fe}^{3+}(aq)$ is shown by ......1...... and the colour of the precipitate is ......2...... . Which row gives the correct answers for gaps 1 and 2?
- A$\dfrac{x}{y}$ , red-brown
- B$\dfrac{x}{y}$ , green
- C$\dfrac{y}{x}$ , red-brown
- D$\dfrac{y}{x}$ , green