A Researcher Using the Twin-Study Method Finds an Average Correlation

A researcher using the twin-study method finds an average correlation of .50 between monozygotic twins' scores on a measure of self-esteem. The researcher finds an average correlation of .30 between dizygotic twins' scores on this measure. The difference between the size of the correlations is statistically significant. What conclusion might the researcher draw from these results?

A) Genetics has more of an influence on self-esteem than environment has.
B) There is evidence for a genetic influence on self-esteem.
C) There is no evidence for a genetic influence on self-esteem.
D) The results are opposite of what would be expected if there were a genetic influence on self-esteem.