The answer is letter D.
Wristwatches or rings are located in the area of the hands which are the necessary body parts when performing electrician tasks. These things are all conductors of electricity which may cause great injury or death to a person. This is one of the basic concepts of working with electrical currents and should not be taken lightly because a person's life is on the line. All the other choices are preventive/safety protocols to be observed when working as an electrician.
