Iron \( (\mathrm{III}) \) catalyses the reaction between iodide and persulphate ions, in which?
A. \( \mathrm{Fe^{3+}} \) oxidises the iodide ion
B. \( \mathrm{Fe^{3+}} \) oxidises the persulphate ion
C. \( \mathrm{Fe^{2+}} \) reduces the iodide ion
D. \( \mathrm{Fe^{2+}} \) reduces the persulphate ion
Choose the most appropriate answer from the options given below:
