In Crum and Langer's Hotel Experiment, the Participants Were

In Crum and Langer's hotel experiment, the participants were:

A) eighty-four female housekeeping staff at seven carefully matched hotels.
B) all undergraduate students in introductory psychology classes at Harvard University.
C) given either ginkgo biloba or a placebo depending on which group they were assigned to.
D) were all male employees selected from the administrative staff of seven carefully matched hotels.