有道英语阅读理解题,应该选哪个?请解析

有道英语阅读理解题,应该选哪个?请解析
I am a writer.I spend a great deal of my time thinking about the power of language—the way it can evoke(唤起) an emotion,a visual image,a complex idea,or a simple truth.Language is the tool of my trade.And I use them all—all the Englishes I grew up with.
31.By saying “Language is the tool of my trade”,the author means that __D____.
A.she uses English in foreign trade
B.she is fascinated by languages
C.she works as a translator
D.she is a writer by profession