Which of these assertions regarding heritability is TRUE? 

• A. The proportion of additive genotypic variance to phenotypic variance is measured by Broad sense heritability.
• B. Twin studies can provide insight into the narrow sense of human trait heritability.
• C. Heritability measures the extent to which genetic variation contributes to the total phenotypic variation.
• D. Both b and c.

Answer: (C)