A comet moves in an elliptical orbit around the Sun. At aphelion A, its distance from the Sun is 1.5×1011m and its speed is 30km s−1. What is its speed (to the nearest km s−1) when it reaches point B where the distance from the Sun is 1.0×1011m?
a) 42 km s−1
b) 45 km s−1
c) 37 km s−1
d) 67 km s−1