单选题

A They are interested in other kinds of reading.

B They are active in voluntary services.

C They tend to be low in education and in income.

D They live in isolated areas.

解析：
细节题。录音对nonreaders的描述包括：“low in education, low in income, live in rural areas”，“isolate themselves from the community”和“seldom belong to local voluntary organizations”。根据这些描述进行逐项判断，选出正确答案为C项。