The correct answer is
C. reduce the friction between its moving parts
In fact, by reducing the friction between the moving parts of the machine, it is possible to reduce the energy wasted due to this friction; therefore, more input energy is converted into useful work, and this will improve the efficiency of the machine.
-- 6 people all trying to push a car out of snow
-- a Tug-o-War with 30 people of different sizes pulling on each end of the rope
-- you and your sister both pulling on the same doll (or Transformer)
-- lifting a book up from the table to a high shelf
taking a book down from a high shelf to the table
(one force is you; another force is gravity)
-- grabbing your big dog by his collar and trying to bring him inside
-- three people at the table all grab the ketchup bottle at the same time
4200000 is your answer hope this helps
The metals will start to rust lol. i think. because this messes up how the metals conduct the flow of the electricity.