（）---should not be allowed to go out at night A.Twelve-years

应该是B,Twelve-year-olds.A和D英语里没有这种表达.C是形容词.B是名词.意思是：12岁的孩子晚上不允许（容许；准许）出门在外.例：－－－Why can't he live here now?－－－Because he can't!－－－Because why?－－－Because eight-year-olds can't be parents!