The heritability of intelligence refers to

A) the extent to which an individual's intelligence is attributable to genetic factors.
B) the proportion of variation in intelligence among individuals that is attributable to genetic variation.
C) the extent to which the intelligence test scores of a large group indicate an average IQ of 100.
D) a general underlying intelligence factor that is measured by every task on an intelligence test.

Heritability refers to the extent to which variation in a trait (such as intelligence) is attributable to genetic variation. Specifically, the heritability of intelligence refers to the proportion of variation in intelligence among individuals that can be attributed to genetic factors. This is typically estimated through studies of identical and fraternal twins, since identical twins share all of their genes and fraternal twins share only roughly 50% of their genes. By comparing the similarities in the intelligence scores of these types of twins, researchers can estimate the heritability of intelligence.