听力原文： The piano and violin are girls' instruments. Drums and trumpets are for boys. Ac

cording to psychologists Susan Onco and Michael Balton, children have very clear ideas about which musical instruments they should play. They find that despite the best efforts of teachers these ideas have changed very little over the past decade. They interviewed 153 children aged between 9 and 11 from schools in northwest England. They asked them to identify 4 musical instruments and then to say which they would like to play most and which they would last like to play. They also asked the children for their views on whether boys and girls should not play any of the 4 instruments. The piano and the violin were both ranked more favorably, by girls than by boys, while boys prefer the drums and trumpets. There was broad agreement between boys and girls on which instruments each sex should play and the reasons vary. And while almost half of all boys said they avoided certain instruments because they were too difficult to play, only 15% of girls gave that as a reason. Earlier studies indicated that very young school children aged between 5 and 7 showed no bias in choosing musical instruments, but their tastes become more clear between the ages of 8 and 10.

Why did Susan and Michael interview children aged between 9 and 11？

A．To find out whether they take music lessons in their spare time.

B．To find out whether they can name four different musical instruments.

C．To find out whether they enjoy playing musical instruments in school.

D．To find out whether they differ in their preference for musical instruments.