[单选题]
The speed of Halley's Come9*g4wk p/d( ,isvjw *iu-lzjdt, while travelinoan5d w0082kad9h -axpw*s lr0k jx1r g in its elliptical orbit around the x*1kwpxd29nla0h r oaarj d w008k-s5 Sun,
A. is constant.
B. increases as it nears the Sun.
C. decreases as it nears the Sun.
D. is zero at two points in the orbit.
