If East is replaced by South-East, it means the direction is shifted 45 degrees clockwise.
Applying the same logic to West:
- West lies at 270 degrees on the compass.
- Shifting 45 degrees clockwise from West (270°) brings us to North-West (315°).
Therefore, when East is replaced by South-East, West will be replaced by North-West.
Conclusion:
The correct answer is North-West.