I believe the answer is D.
You can check your body temperature it is useful in medical field.
Here is a good resource:
https://nhlbi.nih.gov/health/educational/lose_wt/eat/calories.htm
Answer: No
Explanation:
Dr. Fisher was lying on the back thus postmortem staining can be observed on his back. But if the body was moved after death then postmortem staining can also be observed on different parts of the body that can be the front part.