答案：C

 本题考查动词短语辨析。题干是个强调句型，主体部分是nothing but his ten years of hard work_______ his success in his research。句意：十年艰苦的工作导致了他的研究成功。A. refer to 谈到；提及；B. apply to应用于； C. lead to 导致。D. appeal to吸引。