Concept:A statement scale expresses the map scale in words as a distance relation, e.g. 1cm:xkm.Explanation:A complete linear scale has the ground distance represented by each segment indicated clearly.From the map of Joja District, the distance covered by 1cm on the map is 21km on the ground.Hence, the statement form of the scale is 1cm=21km.Answer:Option C: 1 centimeter on the map represents 21 kilometer on the ground.