The scale of a map is a ratio that compares the distance on the map to the actual distance on the ground. For example, a scale of 1:100,000 means that one unit of measurement on the map (such as 1 centimetre) represents 100,000 of the same units on the ground (such as 100,000 centimetres or 1 kilometre). Therefore, the answer to the question is that the scale of the map in statement form is the first option: "1 centimetre on the map represents 1 kilometre on the ground."