In the Ultimatum Game, Single-Blind Protocol Means ____ While Double-Blind

In the ultimatum game, single-blind protocol means ____ while double-blind protocol means _________:

A) The receiver is not aware of the identity of the proposer; neither the receiver nor the experimenter is aware of the identity of the proposer.
B) Neither the receiver nor the experimenter is aware of the identity of the proposer; the receiver is not aware of the identity of the proposer.
C) Both the receiver and the experimenter are aware of the identity of the proposer; neither the receiver nor the experimenter is aware of the identity of the proposer.
D) That the players are playing the dictator game; that the players are playing the ultimatum game.