Concept:The given ratio scale is converted into a statement scale in kilometers.Explanation:The map scale is 1:50,000.This means 1 cm on the map represents 50,000 cm on the ground.Convert 50,000 cm to kilometers:50,000 cm=500 m=0.5 km.Therefore, 1 cm on the map represents 0.5 km on the ground.Answer:A. One centimeter on the map represents half a kilometer on the ground.