下列地形区，全部位于我国北方地区的是：（ ）
A：黄土高原、长江中下游平原
B：华北平原、东北平原
C：云贵高原、东北平原
D：内蒙古高原、四川盆地
—I have difficulty in learning Chinese. Could you give me some help?
—Sure. Reading a lot will help you improve your Chinese.
