Exactly, my girl has a cage covered over with a blanket so she can hide away, but the door is removed.I do not know why anyone would want to lock their dog away in a cage. My dog always sleeps with me. Despite him having his own pen too.
I seen something similar to 2 but it wasn't used for dogs. She was wearing a collar though
If you're using number one you have a very small dog. LOLI would choose No1 I likes to sleep naked with him.