TOEFL Listening: TPO-TOEFL阅读TPO - 17D00Y0S311A1X5RN$

Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information. A. Researchers using observational assessment techniques on infants must not overgeneralize and must base their conclusions on data from many studies. B. On the basis of the data from one or two studies, it seems that some infants develop a particular perceptual ability not observed in others. C. To use data from one or two studies on infant's perceptual abilities, it is necessary to use techniques that will provide conclusive evidence. D. When researchers fail to make generalizations from their studies, their observed data is often inconclusive.