Health and safety question?

Need info on a question i have just had on an exam which one of the following do not have resposibility for implementing cdm regulations in respect of health and safety a electricians on site b clients c designers d contractors just wondering what you would of chose and what does cdm stand for
Answer
Construction (design & management) regs (1994)i am guessing that the client would not have to take notice of the regulations only the contractors??hope this helps