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 pupil automatically gets bigger or smaller to let more or less light in as needed.
 Question: If a bright light were shined in a person's eye, would their pupil size 
 Choices: A)grow 
B)shrink?
Solution:
shrink?