Which three restrictions apply to OSPF stub areas？ （）

• A、 No virtual links are allowed.
• B、 The area cannot be a backbone area.
• C、 Redistribution is not allowed unless the packet is changed to a type 7 packet.
• D、 The area has no more than 10 routers.
• E、 No autonomous system border routers are allowed.
• F、 Interarea routes are suppressed.