单选题 The new model of the car was put into production in 2007, ______ helped to provide another 1400 jobs.
A. that B. when
C. what D. which

【正确答案】 D
【答案解析】[解析] 本题考查非限制性定语从句。在这四个选项中，只有which才能引导非限制性定语从句。