O'Malley Sits in the Corner of a Classroom Observing Children

O'Malley sits in the corner of a classroom observing children at play. Which of the following statements is false ?

A) O'Malley has to make sure that his presence doesn't affect the behavior of the children.
B) O'Malley might be obtaining a more realistic view of how children play by observing them in their natural environment.
C) If O'Malley expects to see a certain behavior he may unintentionally bias the study.
D) O'Malley has random assignment working in his favor.