Correct Answer:
C. Near the Sun
The correct answer is Near the Sun. According to Kepler's laws of planetary motion, a comet's speed is greatest when it is closest to the Sun (at perihelion). This is due to the conservation of angular momentum and the stronger gravitational pull from the Sun at that point. Among the options:
- Far from the Sun: Incorrect; speed is lowest at aphelion (farthest point).
- In the Asteroid Belt: Incorrect; comets do not reach their maximum speed there.
- Near the Sun: Correct; speed is highest at perihelion.
- In the Oort Cloud: Incorrect; comets are very slow in the outer solar system.
Therefore, the correct answer is "Near the Sun".