[单选题]"SeasameStreet"has been called"the longest street in the world". This is because the television program by that name can now be seen in so many parts ofthe world. The program,which went on the air in New York in 1969,uses songs,jokes,andpictures to give children a basic understanding of numbers,letters and humanrelationships.More than 6 million children in the United States watch itregularly.The viewers(观众)include more than half the nation′s children before school age. Manyteacher consider the program a great help,though some teachers find that problems happen when the first-year pupils who have learned from"SeasameStreet"are in the same class with those who have not watched the program.Tests have shown that children who watch it five times a week learn more than those who seldom watch it.In the United States the program is shown at differenthours during the week in order to increase the number of children who can watchit regularly. Why has"Seasame Street"been so much more successful than other children′sshows?Many reasons have been suggested.Perhaps one reason is that motherswatch"Seasame Street"along with their children.But the best reasonfor the success of the program may be that it makes every child watching itfeel able to learn.The child finds himself learning,and he wants to learnmore. "Seasame Street"is so successful mainly because
A.mother watch it with their children
B.it contains songs,stories and jokes
C.it is shown at different hours during the week
D.children are willing and able to learn when watching it