Dr Webb Designs a Research Study in Which the Subjects

Dr. Webb designs a research study in which the subjects and the individuals who interact directly with them do not know who in is the control group and who is in the experimental group. Dr. Webb probably chose this type of research design in order to

A) avoid the need to obtain ethics approval for the study.
B) minimize the possibility of self-report bias.
C) ensure that her sample is not biased.
D) reduce the impact of experimenter bias.