Match the principle with its explanation in Christaller’s model:
| Principle | Explanation |
|---|---|
| A) K=3 | 1) Ensures efficient transportation along routes. |
| B) K=4 | 2) Ensures population balance between higher-order and lower-order centers. |
| C) K=7 | 3) Ensures central places control larger areas and manage lower-order centers. |
| D) K=9 | 4) Applies to retail markets where each higher-order center controls several smaller ones. |
1
A-1, B-2, C-3, D-4
2
A-4, B-1, C-2, D-3
3
A-2, B-3, C-4, D-1
4
A-3, B-4, C-1, D-2