A decision typically has costs/benefits.the oportunity benefit is what you gain from taking an opportunity
While you didn't provide any possible sources, we can expect that biased information would be found when you would look for information from people who are involved in the situation that is being discussed. Imagine a soldier from Germany discussing his viewpoint of World War II. He would most likely give you a biased account. At least, when compared to a postwar historical analysis of that same situation.
The answer is A. Defense
The Defense of Marriage Act.