选B。将问句换成陈述句就是 This farm is ......you visited last week. 很明显句子缺表语,所以首先补充完整,This farm is the one ....you visited last week. 定语从句 you visited last week 修饰 the one ,省略了 关系代词 that / which(,因为关系代词做从句中的宾语),所以选B
选 b. 这题是个定语从句,因为farm 在这里不能做先行词(这句疑问句还原就是:This farm is.....),所以要补一个词来做先行词,这个先行词又要指代farm ,所以就用the one. 如果是下面的句子,就选d.
Is this the farm (that) you visited last week?