【单选题】

The second sentence of the first paragraph, "We have lived through..., off a hound", intends to say that ______.
A．many rivers and creeks have been excessively polluted by various contaminants

B．our lives depend on flaming rivers and caustic creeks
C．we cannot prevent rivers and creeks from being hounded
D．people cannot live without the supply of water from rivers and creeks