Answer:
Correct answer is The nations involved in World War I suffered major losses of life.
Step-by-step explanation:
First option is correct as we can see that many countries had millions of causalities, which leads us to the conclusion that major losses of lives were suffered.
Second and third options are not correct because we can see that both sides had more than million casualties each, and we are not sure how much exactly.
Last option is not correct as United States is in that part of the chart where we have countries that lost between 10 000 and 1 million people.