Jane Rankin Authored a Book That Compared the Advice of Five

Jane Rankin authored a book that compared the advice of five child-rearing experts on six common child-rearing issues. An important influence on their advice appeared to be the ______.

A) data they interpreted from scientific studies
B) lay theories the expert held before experimentation
C) years of experience they had working with children
D) political philosophy they held (e.g., liberal or conservative)