Hello everyone,please look at the big oval or ovals in the picture and let me know which of the following sentences are correct ?
I mean is my sentence correct if I say ....

1. There is an oval in the middle of the carpet.
2. There is an oval in the center of the carpet.
3. There is an oval at the middle of the carpet.
4. There is an oval at the center of the carpet.
5. There is an oval on the middle of the carpet.
6. There is an oval on the center of the carpet.
or anything else
Which one is correct ?