Match the following migration concepts with their correct descriptions:
| Migration Concept | Description |
|---|---|
| 1. Step migration | A. Gradual movement from rural areas to large urban centers |
| 2. Seasonal migration | B. Temporary movement based on agricultural cycles |
| 3. Intervening obstacles | C. Factors that hinder or prevent migration |
| 4. Migration stream | D. Common origin and destination of migration flows |
1
1-A, 2-B, 3-C, 4-D
2
1-C, 2-D, 3-B, 4-A
3
1-B, 2-A, 3-C, 4-D
4
1-D, 2-C, 3-A, 4-B