Concept:Road distances on a map are measured along the actual curved path using a thread, then converted to ground distance using the map scale.Explanation:Lay a thread carefully along the winding road from Dambo to Hume.Mark the point where the thread reaches Hume.Straighten the thread and measure it with a ruler: the length is 15 cm.The map scale shows that 1 cm on the map represents 2 km on the ground.So, the actual road distance is:15×2=30 km.Answer:A. 30 km
