What are the following correct statements about the laws of celestial body movement (in the solar system)?
选项：

A:All planets, including the earth, move in a circular motion at a constant speed around the sun.;
B:All planets revolve around the sun in an elliptical orbit, and the sun is at a focal point of the ellipse.;
C:The area of the sagittal diameter connecting any planet to the sun is equal in equal time;
D:The square of a planet's orbit around the sun is proportional to the cube of its average distance from the sun.;
E:The sun is still.