What is the role of genes in evolution?

I'd say D too, but, it's wording makes me question it as from what I've learned, all Traits are controlled by genes, and putting "only traits that are controlled by genes" imply that there is another control of traits. A seem like one i'd pick too, because, only gens can be acted on by natural selection as to have new traits(traits are inherited because of genes, so it's included.)