A) Grounding is required to complete this method of charging B) rubbing ebonite rod with fur results in electrons transferred from fur to rod C) neutral electroscope becomes negative charged when top is touched with a negative charged object D) if a system contains +4C charge and -6C of charge the net charge of the system is -2C For each of the options which method of charging was used (conduction, friction, induction, all of the above) and explain which physics principle (conservation of energy, mass , charge or nucleons