Based on data, increased recycling of waste, solutions most likely led to the decrease in the amount of waste sent to landfills from 1990 to 2015. The answer is D.
Answer: A self-serving bias
Explanation: Another phenomenon studied in the field of social psychology is simply the tendency of people to attribute positive outcomes to themselves as an expression of their abilities, while attributing bad outcomes to some external "objective" circumstances. This kind of bias is visible in the sports as in this example but not only in sports, it can be seen in school, for example, in college when one considers his / her good grade for the reason that he / she has good predisposition for that material, i.e he / she is good in that material. not because s / he had a hard work of learning it.
Well, Columbus never actually came to America. His ship made land in the Bahamas and Cuba. He thought these islands were Asian islands because the people of Spain were unaware of the Americas, and so he wanted gold. He returned to his country and came back with more men. And killed a lot of people.
Anyway, for the sake of the American education system, I'm assuming the word the teacher is wanting is something like "recognized".