Explanation:
The Olympics take place every two years and countries compete in a variety of sports.
The answer is the last choice, or D.
When you summarize, you're supposed to gather the most important points and rewrite them in a shorter and more simplified fashion. The first three choices include mostly everything you should do when writing a summary. Usually when you summarize, it's for a concluding paragraph, so writing an introductory paragraph wouldn't be it.
It would be the first sentence. chronological means from first to last and the first one would be the only one that makes sense.
