Answer:
i would say b
Step-by-step explanation: if they all slept 4 hours a night then all 9 would have a total of 36 and a night would be 1 so 36 to 1
If your looking for a simplified answer, it would be

.
Hope this helps.
Answer:
![\left[\begin{array}{ccc}11&15&-17\\-1&-4&-4\\17&15&-22\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D11%2615%26-17%5C%5C-1%26-4%26-4%5C%5C17%2615%26-22%5Cend%7Barray%7D%5Cright%5D)
Option D will be your answer

hope it helps...
have a great day!!