To Do Research on the Psychological Effects of Birth Order,what

Multiple Choice

To do research on the psychological effects of birth order,what should a researcher do?​

A) Limit the study to people who attended public schools.
B) ​Limit the study to people whose parents are happily married.
C) ​Limit the study to people from families with at least two children.
D) ​Limit the study to people who are known to be similar to one another in personality.