阅读理解。阅读下列短文, 从给的四个选项 (A、B、C和D) 中, 选出最佳选项。
【2014·临沂3月质量检测】
It can be hard to encourage families of preschoolers to turn off the TV，but there are plenty of highquality shows that promote learning and positive relationships rather than violence，researchers noted.
