Final answer:
Between 50 and 75 percent of the variation in intelligence scores is attributed to genetics, according to current estimates.
Step-by-step explanation:
Current estimates indicate that between 50 and 75 percent of the total variation among intelligence scores can be attributed to genetic factors. This conclusion comes from examining correlations of IQ scores of unrelated vs. related persons reared apart or together.
The heritability of intelligence suggests that while genetics play a significant role, environmental influences also contribute to the manifestation of cognitive abilities. Therefore, the correct answer to the student's question is option 3.