Suppose That Researchers Estimate the Unique Environment Influence on a Trait

Suppose that researchers estimate the unique environment influence on a trait by finding the proportion of variance that remains after genetic and common environment influences have been calculated.This estimate of unique environment influence could include which of the following sources?
1) Imperfections in the measurement of the trait
2) Random chance during development
3) Various specific features of the environment that differ within families

A) 3 only
B) 1 and 2 only
C) 1 and 3 only
D) 2 and 3 only
E) 1,2,and 3