单项选择题

Questions 17 to 20 are based on the following passage. At the end of the passage ,you will be given 20 seconds to answer the questions.
Now listen to the passage.

What has happened to the children of working mothers

A.They are in government-supported day care centers.
B.They are in private day care centers.
C.Their grandmothers take care of them.
D.They are sent to boarding school.