请教一个CS题目

OG12上练习题第22道，原题是这样：
PLAN：concerned about the welfare of its senior citizens,the government of Runagia decided two years ago to increase by 20 percent the government-proviede pension paid to Runagians age sixty-five and older.

  RESULT: many Runagian senior citizens are no better off financially now than they were before the increase.

  FUTHER imformation: the annual rate of inflation since the pension increase has been below 5 percent,and the increased pension has been duly received by all eligible Runagians.

in light of the further imformation,which of the following ,if true, does most to explain the result that followed implementation of the plan ?

其他选项可以轻松排除，有两个选项我认为存在一些疑问：
C：The prices of goods and services that meet the special needs of many senior citizens have increased at a rate much higher than the rate of inflation .
D: the pension increase occurred at a time when the number of Ranagians age sixty-five and older who were living below the poverty level was at an all-time high.

  我当时选的是D，原因如下：
1、处在领这个pension的人的数量大大多于以前，即使是pension本身increase 20%, 由于分子大大增加，也可能导致pension to per people 降低，因此decrease the living level.
2、而c,也有可能，只是因为（1）inflation decreased 5%,（2）即使prices of goods and services meet the special need of these 大大增加，也不一定无法降低PENSION的实惠。因为不管这些有什么特殊需求，水、实物、交通、健康这些普通需求还是占多数，这些价格都在INFLATION的范围内。

  所以，我觉得其实D比C更好点，哪位NN帮我分析解释一下，谢谢。