Morrison was in a bike accident and was hospitalized three months ago. His helmet had not been properly fastened and did not protect his head from the force of the fall. Morrison fractured his hip, broke a leg, and severely injured his head. Since the accident, he has failed to respond to any treatment and has been in a coma. What is likely to have led to Morrison's condition?

a. The cerebrum is injured and is hampering thinking and language.
b. The fall has injured the reticular formation in his brain.
c. The hippocampus is not storing new information.
d. The hypothalamus is not regulating body temperature.