阅读理解。

     Shu Pulong has helped at least 1,000 people bitten (咬) by snakes, "It was seeing people with snake bites

(伤口) that led me to this career," he said.

     After his army service, Shu entered a medical school and later became a doctor of Chinese medicine. As

part of his studies he had to work in the mountains. There he often heard of people who had their arms and

legs cut off after a snake bite in order to save their lives. 

Which of the following words can take the place of the word "career" in the first paragraph(段)?

A. conclusion

B. story

C. incident

D. job