Which One of the Following Findings Is the Best Evidence

Which one of the following findings is the best evidence that environment plays an important role in determining intelligence?

A) Identical twins raised by different families from birth have more similar IQs than fraternal twins raised together.
B) Nontwin siblings raised together have more similar IQs than nontwin siblings raised apart.
C) Children have IQs that are more similar to the IQs of their parents than to the IQs of their siblings.
D) Children adopted from different biological parents but raised by the same adoptive parents have small IQ correlations as adults.