请教一题GWD-8-Q19: GWD-2-12

Which of the following most logically completes the passage?

Concerned about financial well-being of its elderly citizens, the government of Runagia decided two years ago to increase by 20 percent the government-provided pension paid to all Runagians over 65.  Inflation in the intervening period has been negligible, and the increase has been duly received by all eligible Runagians.  Nevertheless, many of them are no better off financially than they were before the increase, in large part because ________.

A.        They rely entirely on the government pension for their income

B.         Runagian banks are so inefficient that it can take up to three weeks to cash a pension check

C.        They buy goods whose prices tend to rise especially fast in times of inflation

D.        The pension was increased when the number of elderly Runagians below the poverty level reached an all-time high

E.         In Runagia children typically supplement the income of elderly parents, but only by enough to provide them with a comfortable living

题干还是比较明白的，但是选项感觉都没什么关系，不知道为什么选E呢，请指教

E的意思是说eligible（elderly citizens）的收入=government-provided pension +子女supplement

而子女只会提供enough to provide them with a comfortable living 也就是说子女的supplement会根据pension的变化作出相应的调整（此消彼长） 从而使总收入没有变化