题目内容：
The meaning of the sentence “Even exercise professionals concede half a point here.”(Line 3, Para.2) is that __________.(本题1.5分)
A、
they agree that the calories in a small piece of pastry can be difficult to work off by exercise.
B、
they are not sufficiently informed of the positive role of exercise in losing weight
C、
. they also think that exercise is not an easy means to achieve the target of weight reduction
D、
they are not fully convinced that dieting can help maintain their new weight
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