140. 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
KEY: C
我选的是B，请问这里哪里体现出来转折的关系要用yet啊？我觉得递进关系更明显。
请牛牛指教！ | 
