A Roche Lobe Is an Imaginary Boundary Around Each Star

A Roche lobe is an imaginary boundary around each star in a close binary system

A) encompassing the mass gravitationally bound to that star.
B) that marks the limit outside which planets cannot form.
C) that marks the limit inside which planets cannot form because they would be torn apart by the star's gravity.
D) that marks the limit of each star's gravitational pull: As long as each star is within its own Roche lobe, the stars will have no effect on each other.