I think it's A. focus each paragraph on one main idea. I hope this helps if it's the wrong answer I'm sorry.
Answer:
We have had a lot of troubles in the past. World Wars, Flu epidemics. Countries have changed. Countries allied each other to defeat others. But the only time when all the countries come together to defeat the same enemy -- Corona virus.
The theme expressed in this paragraph is that
even wise people do foolish things at times.those who sacrifice for others are great people.sacrificing one’s most prized possessions is foolish.<span>wise people are often those with the fewest possession</span>
