单项选择题

Questions 18 to 20 are based on the following passage. At the end of the passage, you will be given 15 seconds to answer the questions.
Now, listen to the passage.

Children over 18 years old who are still eligible for child benefit must be ______.

A.from single parent families
B.in low-income families
C.in full-time education
D.under training for work