Which Statement Best Answers the Question, "Do Environmental Factors Cause

Which statement best answers the question, "Do environmental factors cause schizophrenia?"

A) "Since concordance rates are less than 50 percent in identical twins, environmental factors must play a causal role."
B) "Environmental factors such as poor family communication are usually caused by schizophrenia, not the other way around."
C) "There is little evidence that environmental factors contribute to the disorder."
D) "If environmental influences play a causal role, it is probably in adulthood, close to the time when symptoms first appear."