Two conducting spheres of different radii each carry a charge +Q. Which of the following occurs when the two spheres are touched together? ( )
选项：

A:No charge flows.
B:Positive charge flows from the larger sphere to the smaller sphere until the electric field at the surface of each sphere is the same.
C:Positive charge flows from the smaller sphere to the larger sphere until the electric field at the surface of each sphere is the same.
D:Positive charge flows from the larger sphere to the smaller sphere until the electric potential at the surface of each sphere is the same.
E:Positive charge flows from the smaller sphere to the larger sphere until the electric potential at the surface of each sphere is the same.