What's the difference between the approaches of Nancy Bayley and Emmi Pikler when it comes to evaluating babies' development? A. Pikler's evaluation methods take into account that babies should be confined for safety, while Bayley's are based on letting infants have free movement. B. There's not much difference between their approaches—Bayley was a student of Pikler. C. Pikler's evaluation methods are based on testing situations while Bayley's are meant to be diagnostic. D. Bayley evaluates babies by manipulating them to see what they do; Pikler observes what they do on their own.