Right off the bat (haha), we can eliminate B as an answer choice because adults are clearly part of the population; in fact, it says in the background information that their entire population is made of adults. A population, in this context, is the group being researched.
D isn't the correct answer; the fact that adults are the target population doesn't validify anything.
C doesn't entirely prove its point because there are other factors that go into the game being biased. In fact, I would say that this study is biased because the board members only attended 1 game when there are 18 teams. Their data will only pertain to fans of the 2 teams playing each other, and not represent the population as a whole.
A would be my answer for reasons stated above.
