The following questions present a sentence

问题：

The following questions present a sentence, part of which or all of which is underlined. Beneath the sentence, you will find five ways of phrasing the underlined part. The first of these repeats the original; the other four are different. If you think the original is best, choose the first answer; otherwise choose one of the others.

These questions test correctness and effectiveness of expression. In choosing your answer, follow the requirements of standard written English; that is, pay attention to grammar, choice of words, and sentence construction. Choose the answer that produces the most effective sentence; this answer should be clear and exact, without awkwardness, ambiguity, redundancy, or grammatical error.

Providing adequate public health-care facilities is a crucial task in a county like Travis, where more than 60 percent of household incomes are below the poverty line.（）

A. where more than 60 percent of household incomes are

B. where more than 60 percent of household income is

C. which has more than 60 percent of the household incomes

D. where they have more than 60 percent of household income

E. where more than 60 percent of them have household incomes