Which of the following statements support role of environment in the development of a child?

• A. Some students quickly process information while others in the same class do not.
• B. There has been a steady increase in students' average performance on IQ tests in last few decades.
• C. Correlation between IQs of identical twins raised in different homes is as high as 0.75.
• D. Physically fit children are often found to be morally good.