Fact 1: Riding a bike does not cause pollution. Fact 2: Pollution is anything that spoils the environment. Given the two facts above, what does not spoil the environment?

Select from the following. A). Operating a factory; B). Driving a car; C). Riding a bike; D). food and shelter; E). hydrate their cells; F). lowered energy cost; G). Burning a fire; H). peachleaf willow;
Answer:
C).