What Is the Evidence That Suggests There Is Some Genetic

What is the evidence that suggests there is some genetic component to explanatory style?

A) Learned optimism scores are more highly correlated for identical than fraternal twins.
B) Learned optimism scores are moderately correlated between extended family members.
C) Learned optimism scores among siblings are not highly correlated.
D) Learned optimism scores are highly correlated for parents and their children.