男性，45岁。反复胸闷、心悸、端坐呼吸、胸腔稠液半年。查体：呼吸短促，两肺广泛细湿啰音，心浊音界扩大，心率100次/分，呈舒张期奔马律，偶发前期收缩。X线胸片示心胸比率0．65，两肺水肿。心电图示完全f生左束支传导阻滞，偶见室性期前收缩。超声心动图提示左心室明显增大，舒张末期内径70mm，左室整体运动减弱，射血分数（EF）为24％，缩短分数（FS）为12％。

为明确诊断，还需要进行哪项检查（）

A.MRI

B.CT

C.心肌酶谱

D.心内膜心肌活检

E.以上都不是

Dina Borzekowski made a study of a group of third-grade students from six American 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 of children’s bedrooms, or not putting them there, may be helpful," said Borzekowski. "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 did Borzekowski’s study last
[A] One year.
[B] Three years.
[C] Six years.