Mr McLean, a Fourth Grade Teacher, Finds That the Students

Mr. McLean, a fourth grade teacher, finds that the students whom he expects to perform well generally do perform well. Which of the following are possible explanations for this correlation?

A) Mr. McLean's expectations lead him to treat certain students differently than others.
B) Mr. McLean's perception of his students' abilities is accurate.
C) Mr. McLean's expectations are biased in favor of white middle-class children.
D) All of the above are true.