repair作“修缮”解,有时可数有时不可数.比如：
They agreed to pay the costs of any repairs.(引自《牛津高阶英汉双解词典》)
The bridge will remain closed until essential repair work has been carried out.[在基本修缮工作完成之前,这座桥暂时关闭.（出处同上) ]
补充：选rebuilt是错的,因为语法上for只跟名词和动名词（v-ing）.选B而不是A说明repair在句中表示泛指,故用复数.