A positive point charge `+Q` is fixed in space .A negative point charge `-q` of mass `m` revolves around a fixed charge in elliptical orbits .The fixed charge `+Q `is at one focus of the ellipse.The only force acting on negative charge is the electrostatic force due to positive charge is the electrostatic force due to positive charge.Then which of the following statement is true

Options

A. Linear momentum of negative point charge is conserved
B. Angular momentum of negative point charge about fixed positive charge is conserved
C. Total kinetic energyofnegative point charge is conserved
D. Electrostatic potential energy of system of both point charges is conserved