If Shared Environmental Influences Alone Contribute to the Expression of a Trait

Multiple Choice

If shared environmental influences alone contribute to the expression of a trait, which of the following patterns of correlations would be observed?

A) 1.00 for identical twins raised together but a somewhat lower correlation for those raised apart
B) 1.00 for both identical and fraternal twin pairs raised together but no correlation for those pairs raised apart
C) 1.00 for identical twins and .50 for fraternal twins raised together and raised apart
D) no significant correlation between identical twins or fraternal twins, regardless of whether they were raised together or apart