单选题 How is in the investigations carried out by historians in 1950s different from previous studies?

A、 They had new findings.
B、 They expanded the period defined as pre-industrial Europe.
C、 They investigated the common people who took up the majority of the population.
D、 The investigations were on the kings, generals ,judges, nobles, bishops, and local magnates.

【正确答案】 C

【答案解析】根据文章第一段第一句可知五十年代的历史学家第一次对工业化前的欧洲的平民进行调查研究，而以往对于工业化前的欧洲的研究多集中在只占人口2%--3%的王宫贵族上。[A]和[B]文章未提及。[D]与文意不符，这类是以前历史学家研究的对象，并不是这次研究的对象。