When Examining the Differences That Exist Among Older, Younger, or Middle

When examining the differences that exist among older, younger, or middle children, the best rule of thumb is

A) to emphasize birth order as an explanation.
B) to ignore birth order in the explanation.
C) to include birth order as one factor in many, including number of siblings, age of siblings, temperament of siblings.
D) to emphasize intelligence over any other characteristic.