The correct answer is the medulla oblongata.
The medulla oblongata is situated in the brainstem, partially inferior and at the front of the cerebellum. It is a cone-shaped neuronal mass accountable for involuntary activities ranging from vomiting to sneezing.
The medulla comprises the respiratory, cardiac, vasomotor, and vomiting centers, and thus deals with the autonomic activities of heart rate, breathing, and blood pressure.
As it controls involuntary activities, like sneezing. Thus, if one is not able to sneeze then it shows that the medulla oblongata is missing or defected.
