Which of the following color is used for radiation hazard? (A) Red (B) Orange (C) Green (D) Purple

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Symbol can be magenta or black, on a yellow background. Sign must be posted where radioactive materials are handled or where radiation-producing equipment is used. Sign is used as a warning to protect people from being exposed to radioactivity. 

(D) Purple on yellow background according to ANSI/NEMA Z.1- (R) and OSHA