Answer: Opinion
This comes from a magazine, so it automatically makes it opinionative if we are going by realistic standards. But based on the paragragh there are facts that are correct, however, this seems very focused on the U.S. so there is bias. Out of the many countries that helped in D-Day, the U.S. troops have some of the most casualties and most trouble gaining a foothold in their beaches they landed in. This, however, could also be due to increased defenses in the area they landed.
