You will be given a definition of a task first, then an example. Follow the example to solve a new instance of the task.
You are given a short paragraph, a question and two choices to answer from. Choose the correct answer based on the paragraph and write the answer(not the key).

Paragraph: Many of the worlds people live with water scarcity, and that percentage will increase as populations increase and climate changes.
 Question: John's town used to have lots of water, back when there were only a few hundred people. However, now that the town holds several thousand people, the water availability is 
 Choices: A)scarce 
B)plentiful
Solution: scarce
Why? Based on the information given in the paragraph, population growth will make water more scarce, so that is the correct answer.

New input: Paragraph: The main law is the law of superposition. This law states that deeper rock layers are older than layers closer to the surface.
 Question: When you go into a cave, the rocks at deeper levels are _____ than the rocks on the surface. 
 Choices: A)younger 
B)older
Solution:
older