Genome-Wide Associated Studies (GWAS) Look at the Potential Role of Genetics

Genome-wide associated studies (GWAS) look at the potential role of genetics in drug addiction by

A) focusing on the potential involvement of genes that are selected based on the biochemical mechanism or mechanisms that underlie addiction.
B) looking for chromosomal regions that tend to associate with addiction, and for mutations.
C) investigating the entire genome in search of alleles that associate with addiction.
D) All of the above