A jogger runs along a straight and level road for a distance of 8.0 km and then runs back to her starting point. The time for this round-trip is 2.0 h. Which one of the following statements is true?
(a) Her average speed is 8.0 km/h, but there is not enough information to determine her average velocity.
(b) Her average speed is 8.0 km/h, and her average velocity is 8.0 km/h.
(c) Her average speed is 8.0 km/h, and her average velocity is 0 km/h.