In a Double-Blind Experiment

In a double-blind experiment:

A) the researcher conducting the post-treatment assessment does not know which participants were given the treatment and which had been assigned to a wait-list control.
B) the researchers conducting the treatment send their data to an impartial laboratory for analysis;they are kept blind as to the results of the study until publication.
C) both the experimenter and the participant are uninformed about which treatment the participant is receiving.
D) participants never know if they were given the treatment or not.