求问一道xdf蓝皮逻辑题，怎么也想不通

nightprayer1973

A society’s infant mortality rate is an accepted indicator of that society’s general health status. Even though in some localities in the United States the rate is higher than in many developing countries. In the United States, overall the rate has been steadily declining. This declines does not necessarily indicate, however, that babies in the United States are now, on the average, healthier at birth than they were in the past.
　　Which one of the following reasons, if true, most strongly supports the claim made above about the implications of the decline?
　　A. The figure for infant mortality is compiled as an overall rate and thus masks deficiencies in particular localities.
　　B. Low birth weight is a contributing factor in more than half of the infant deaths in the United States.
　　C. The United States has been developing and his achieved extremely sophisticated technology for saving premature and low-birth-weight babies, most of whom require extended hospital stays.
　　D. In eleven states of the United States, the infant mortality rate declined last year.
　　E. Babies who do not receive adequate attention from a caregiver fail to thrive and so they gain weight slowly.

题干意思是 在美国有些地方婴儿死亡率比发达国家还高，但是总体的婴儿死亡率在稳步下降，但是这个下降不能说明美国婴儿比以前的出生时更健康了，问支持选项。正确答案是C，我选了A。
解析是，婴儿死亡率受两个因素影响，一是出生时的健康状况，二是后期护理，后期护理进步导致的死亡率下降不能说明婴儿更健康了~但是 我做题的时候怎么会想到婴儿死亡率就是受这两个因素影响啊……现在看着答案 还是觉得A有道理，求大家解惑！

nightprayer1973

自己顶一下

nightprayer1973

你是认真的吗

关注结论：This declines does not necessarily indicate, however, that babies in the United States are now, on the average, healthier at birth than they were in the past.

结论是从平均层面出发的，所以A的内容其实就是结论已经考虑在内的情况

C则引入了其他影响婴儿健康的因素，合理~

nightprayer1973

你是认真的吗 发表于 2017-12-4 07:51
关注结论：This declines does not necessarily indicate, however, that babies in the United States are ...

比心心！