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, yet (E) and these families can no longer afford to buy homes, for 答案是c 但我觉得b也挺好,尤其我觉得是递进,而不是转折