Match the items in Column I with the items in Column II, and assign the correct code.
| Column I | Column II |
| A. Cyanide process | 1. Ultrapure Ge |
| B. Froth flotation process | 2. Dressing of ZnS |
| C. Electrolytic reduction | 3. Extraction of Al |
| D. Zone refining | 4. Extraction of Au |
| 5. Purification of Ni |
Codes
| A | B | C | D | |
| 1. | 4 | 2 | 3 | 1 |
| 2. | 2 | 3 | 1 | 5 |
| 3. | 1 | 2 | 3 | 4 |
| 4. | 3 | 4 | 5 | 1 |
