In the Late 19th Century, Researchers Kept Baby Biographies

In the late 19th century, researchers kept baby biographies.How did this approach to studying child development improve on the earlier philosophers' approaches?

A) This approach was entirely objective.
B) This approach met the rigorous requirements of the scientific method we have today.
C) This approach viewed children as passive recipients of learning.
D) This approach was a less limited and unsystematic form of studying child development.