Americans spend their free time in various ways.America is a country of sports---of hunting, fishing and swimming, and of team sports like baseball and football. Millions of Americans watch their favorite sports on television. They also like to play in community orchestras（管旋乐队）, make their own films or recordings, go camping, visit museums, attend lectures, travel, garden, read, and join in hundreds of other activities. The people also enjoy building things for their homes, sewing their own clothes, even making their own photographs. They do these things for fun as well as for economy.But as much as Americans enjoy their free time, the country is at the same time a "self-improvement" country.More than 25 million adults continue their education, chiefly by going to school in the evening, during their own free time, at their own expense.Added to the time spent on personal activities, Americans also devote a great amount of their time to the varied needs of their communities. Many hospitals, schools, libraries, museums, parks, community centers, and organizations that assist the poor depend on the many hour citizens devote to these activities, often without any pay. Why do they do itThere are several answers. The idea of cooperating and sharing responsibility with one another for the benefit of all is as old as the country itself.When the country was first founded in 1776, it was necessary for the settlers to work together to live. They had crossed dangerous seas and risked all they had in their struggle for political and religious freedom. There remains among many Americans a distrust of central government. People still prefer to do things themselves within their communities, rather than give the government more control.Sometimes people offer their time because they wish to accomplish something for which no money is paid, to do something that will be of benefit to the entire community. It is true that some people use their leisure because they are truly interested in the work; or they are learning from the experience.No matter what the reason is, hundreds of thousands of so called leisure hours are put into hard, unpaid work on one or another community need. This passage is mainly about ______.

A. Why America is a country of sports.
B. How Americans spend their free time.
C. Why America is a "self-improvement" country.
D. How Americans are devoted to their community activities.