【单选题】

DinaBorzekowsld made a study of a group of third-grade students from sixAmerican schools.During a school year, nearly 400 students and their parents were asked to report on whether they had such things as televisions and computers in the home, as well as how often the child used them. The children’s language ability was tested (测验) twice over the year.Children who had a television set in the bedroom but did not have a computer at home scored (得分) the lowest, while students without TV in the bedroom but with a computer at home scored the highest. Students who had a television in the bedroom over the school year scored lower than those who had their TV taken away during the same time.

"This study suggests that taking TV sets out children’s bedrooms, or not putting them there, may be helpful," saidBorzekowski. "While this study does not prove ( 证 明) that bedroom TV was the reason for the lower test scores, it suggests that children shouldn’t have TV in their bedrooms. It also suggests that a home computer may help a child’s test scores. The best way was having both: no TV in the bedroom and also a home computer to use.\
How long didBorzekowski’s study last
[A] One year.
[B] Three years.
[C] Six years.