题型分类：事实信息题

原文定位：定位词 before the arrival of European settlers。用定位词定位到第五段的第一句。prior to 对应题干中的 before。第一句提出在欧洲人在大平原地区定居和耕作之前，浣熊在该地区的河流、溪流沿岸以及该地区的东南部树林里存在着。紧接着第二句说除了马尼托巴省南部地区之外，整个加拿大都难以找到浣熊。

选项分析：

C 选项说浣熊 were not found in most of Canada，对应第二句 With the possible exception of the southern part of the province of Manitoba, their absence was notable throughout Canada。

A 选项说浣熊 were widely distributed throughout the region 在该地区广泛分布。而第一句和第二句都说明此时浣熊存在的区域有限。该选项与原文描述不符。

B 选项说浣熊 were found mostly in areas of open prairie，文中没有提到在开阔的草原上存在的信息，属于无中生有。

D 选项说浣熊 had not yet reached the wooded areas of the southeastern portion of the region，而第一句中提到 Prior to Europeans settling and farming the Great Plains region…, raccoons probably were just found along its rivers and streams and in the wooded areas of its southeastern section 因此该选项与原文描述不符。