[求助]885 section D-02

As the housing affordability gap widens, middle-income families are especially hard-hit,and these families can no longer qualify to buy homes, and rising rental rates force them to use far more than the standard 25 percent of their incomes for housing, leaving them with no equity or tax write-offs to offset the expenditures.

(A) and these families can no longer qualify to buy homes, and
(B) since these families can no longer afford to buy homes, furthermore
(C) for these families can no longer afford to buy homes, yet
(D) and these families can no longer afford to buy homes; however,
(E) and these families can no longer afford to buy homes, for

The given answer is C, but I don't get the structure of it. What are the main clause and subclause? Can some NNs please explain the structure of this sentence? Thanks a lot.

I apologize for using English here. My PC can read but not type in Chinese.

for 作为连词，就是because,since的意思。

这里的结构没什么难的啊 as引导的状语，句子1，for(做连词）句子2，yet(连词)句子3,状语。

了解清楚这句话的意思就很清楚各（分）句之间的逻辑关系了！

随着这个housing affordability 差距的加深，中等收入的家庭受到特别大的打击，因为(for 解释前面这点)这些家庭再也无力购买房屋，但是（雪上加霜啊！）日益上涨的租金却迫使他们把25%的收入都花在了房租上，使得他们。。。