The correct answer is a) High ranges.
Aromatic crops like vanilla and patchouli are cultivated in high ranges because they require a warm, humid climate with plenty of rainfall. The high altitudes of these regions provide the ideal conditions for these crops to grow.
Option b) Coastal regions is incorrect because these regions are typically cooler and drier than high ranges. This would not be ideal for the cultivation of aromatic crops.
Option c) Midlands is incorrect because these regions are typically located between high ranges and coastal regions. The climate in these regions is not as ideal for the cultivation of aromatic crops as the climate in high ranges.
Option d) Dry areas is incorrect because these regions do not receive enough rainfall for the cultivation of aromatic crops.