Maya Participates in a Double-Blind Study on the Effectiveness of a New

Maya participates in a double-blind study on the effectiveness of a new time-release antidepressant medication. Once a week, she receives a small white pill from Dr. Stanley, which she takes immediately. In this type of study, which of the following is true?

A) Dr. Stanley does not know whether Maya receives a real substance or placebo until the experiment is over.
B) Maya does not know the purpose of the study being conducted until it is over.
C) Dr. Stanley never meets Maya or knows she is in the study until the experiment is over.
D) Maya knows whether the white pill is a real substance or a placebo throughout the study.