A small positively charged ball of mass m is suspended by a long insulating thread of negligible mass. Other positively charged small ball is moved very slowly from a large distance (along horizontal direction) until it is at original position A of first ball. As a result the first ball rises by h to position B such that $$h \ll \ell$$. Choose the correct statement (s)

A

Electrostatic energy of system of charges is 2 mgh

B

Total work done on system to bring two balls in their final position is mgh

C

Total work done on the system to bring two balls in their final position is 3 mgh

D

Work done on system to bring two balls in their final position does not depend on the magnitude of charges explicitly