I believe the answer is D.
It would most likely be to reverse aging for older people, or to look better for younger people, while still being one age.
Answer:
C. Distance between two place
Explanation:
Scale represent the ratio of size in a map. For example, if a map contains a scale of 1 : 100,000, it means that 1 cm in the map represent 1 Km in actual distance.
This can be used to measure distance between two places.
For example, Let's say that in a 1:100.000 map the distance between Washington and New York is around 369 cm. This means that the we can measure actual distance between Washington and New York by using the map alone (which is around 369 Km)
