Medulla oblongata is the lowest part of the brainstem (hindbrain) and is vital to several functional regulations that coordinate our life processes.
Reticular activating system (B) is a network of neural centers including parts of cerebrum and cerebellum, not just medulla oblongata.
Pineal gland (C) produces melatonin) and is located deep within the central part of the brain; and it is not located in the medulla oblongata.
Corpora quadrigemina (D) is located in the midbrain and not in the medulla oblongata.
Therefore, options B, C & D are incorrect.
The medulla oblongata contains vital centers that control heart action, blood vessel diameter and respiration (A). Jeffery’s poliomyelitis infection’s has critically affected medulla oblongata’s ability to coordinate key regulatory activities of circulatory and respiratory system. Thus, doctors have arrived at the dire prognosis that Jeffery might not live long.
Therefore, option (A) is correct.