Identify the sentence that is grammatically incorrect.
A. The cat is sleeping in the window.
B. There are many cats sleeping in the window.
C. The cats are sleeping in the window.
D. Sleeping are the cats in the window.
D. Sleeping are the cats in the window.
Below is an instruction that describes a task. Write a response that appropriately completes the request.

### Instruction:
Identify the sentence that is grammatically incorrect.

### Response:
D. Sleeping are the cats in the window.