单选题 A person's dietary consumption of cholesterol and fat is one of the most important factors determining the level of cholesterol in the person's blood (serum cholesterol). Serum cholesterol levels rise proportionally to increased cholesterol and fat consumption until that consumption reaches a threshold, but once consumption of these substances exceeds that threshold, serum cholesterol levels rise only gradually, even with dramatic increases in consumption. The threshold is one fourth the consumption level of cholesterol and fat in today's average North American diet.
The statements above, if true, most strongly support which one of the following?

A、 The threshold can be lowered by lowering the dietary consumption of cholesterol and fat.
B、 People who consume an average North American diet cannot increase their consumption of cholesterol and fat without dramatically increasing their serum cholesterol levels.
C、 People who consume half as much cholesterol and fat as in the average North American diet will not necessarily have half the average serum cholesterol level.
D、 Serum cholesterol levels cannot be affected by nondietary modifications in behavior, such as exercising more or smoking less.
E、 (E) People who consume less cholesterol and fat than the threshold cannot reduce their serum cholesterol levels.

【正确答案】 C

【答案解析】[解析] 根据在阈限以上血清胆固醇水平随胆固醇与脂肪量的消耗的增加而变缓可以推出(C)为正确答案。(A)、(B)和(E)与本题短文中陈述的内容相矛盾；(D)不能从本题的段落中合理地推出。