Research on the Differences in Personality Between First- and Later-Born

Research on the differences in personality between first- and later-born children explains such findings by saying

A) they may be linked to contrasts in the parenting styles used with each child.
B) later-born children tend to have easier temperaments.
C) parents tend to be more authoritarian with later-born children.
D) there are no definite personality differences found between first- and later-born children.