The commercial method of preparation of potassium by reduction of molten `KCl` with metallic sodium at `850^(@)C` is based on the fact that
A. potassium is solid and sodium and solution distils off at `850^(@)C`
B. potassium being more volatile and distile and distils off thus shifting the reaction forward
C. sodium is more reactive than potassium at `850^(@)C`
D. `sodum has less affinity to chloride ions in the presence of potassium ion