根据以下内容 回答下列各题。 According to the passage the extinction of whales is caused

根据以下内容，回答下列各题。 According to the passage, the extinction of whales is caused by__________

A. man"s continuous evolution process

B. the changing living conditions in nature

C. people"s excessive hunting and killing

D. the demand from a booming economy

请帮忙给出正确答案和分析，谢谢！