单选题 Many pregnant women suffer from vitamin deficiency, but this is frequently not due to vitamin deficiency in their diets; most often it is because they have higher requirements for vitamins than do the rest of the population.
The best criticism of the reasoning in the statement above is that it

A、 fails to specify the percentage of pregnant women who suffer from vitamin deficiency.
B、 gives insufficient information about why pregnant women have higher vitamin requirements than do other groups.
C、 fails to employ the same reference group for both uses of the term "vitamin deficiency. "
D、 provides insufficient information about the incidence of vitamin deficiency in other groups with high vitamin requirements.
E、 (E) uses "higher requirements" in an ambiguous manner.

【正确答案】 C

【答案解析】[解析] 本题的段落中有两个地方提及维生素缺乏：第一是怀孕妇女的维生素缺乏，指的是怀孕妇女身体内的维生素缺乏；第二是食物中维生素的缺乏，指的是食物中维生素的含量少。这两处的参照物很明显是不同的。(C)指出了这一点，因此(C)正确，其他的四个选项都不能对本题段落的推理构成批评。