Researchers Who Claim That Siblings Reared in the Same Family

Researchers who claim that siblings reared in the same family show little resemblance in parent-rated temperament also assert that

A) peers are a more powerful influence on children's behavior than parents.
B) parenting influences cannot be measured easily.
C) parenting has different effects on different children.
D) the effects of parenting overshadow any impact of the child's genetic makeup or the peer culture.