A Comet Is Found to Move in an Elliptical Orbit $\times$

Multiple Choice

A comet is found to move in an elliptical orbit. When the comet's aphelion distance is 2.5 AU, it has a velocity of 100 m/s. The point of closest approach is 0.5 AU from the Sun. The velocity of the comet at the point of closest approach is

A) 2.5 km/s.
B) 80 m/s.
C) 5.0 $\times$ 10² m/s.
D) unknown; more information about the orbit is necessary to answer this question.