问题
单项选择题
A．Because they think people are usually very interested in sports.
B．Because they are not interested in how jet lag affects businesspeople.
C．Because baseball teams want to know how to win more games.
D．Because it is difficult to measure how jet lag affects other types of travelers.
答案
参考答案：D
解析：[听力原文]
According to the report, why did researchers study jet lag in baseball