Which choice correctly identifies the structures in the brainstem? a. reticular formation, thalamus, amygdala b. medulla, pons, reticular formation c?

The parts of the brain stem are the mid brain,reticular formation, pons and the medulla. The brain stem is located in the posterior part of one's brain adjoining the spinal cord. Hope this would be of help and this is the right answer.

The brainstem is a complex part of the brain, located in the back. It is constituted by many parts: 
From the top:
The midbrain: which it consists of the tectum (which itself contain reticular formations), the tegmentum, and the ventral tegmentum. 
The pons: which link between the medulla oblongata and the midbrain.
Medulla oblongata.

So the right answer is that It is constituted by the medulla, pons, and ventricular formation.