One particular confound for the use of an adoption study of heritability is the phenomenon of placement, in which a child is placed in a home that is similar to the home of the biological parents.
a) unilateral
b) forced
c) matched
d) selective

D) selective

Explanation:

The selective placement in the adoption studies refers to practice by which the adoption agencies tend to match some definite characteristics of the adopted child's adopted parents than that of child's biological parents.

It results in the correlation of the environments between the biological relatives raised in two different homes.

For example, when the child is placed in a home which is similar to the home of the biological parents.

wavelegth as in spectrum red oygbiv

i think it's 35 meters