Researchers at Pharm-X, a pharmaceutical company, are testing and comparing the effects of Drug A and Drug B on participants' allergies. The researchers are using a double-blind procedure to conduct their test. This means that
a. The participants know which drug they are receiving.
b. The experimenters administering the drugs know which drug the participants is receiving.
c. Neither the participants nor the experimenters know which drug the participant is receiving.
d. The participants and experimenters are physically separated from each other during the course of the experiment.