Correct! This patient has suffered severe damage to all parts of his brain, but the comitant esotropia with full ocular ductions suggests diencephalic dysfunction. There has been a breakdown of fusion, such that the balance between convergence and divergence has been upset. A lesion in the cerebral hemispheres could also upset that balance, but you were not offered that answer option here. Bilateral sixth nerve palsy is a common mistaken explanation for esotropia, but that should reduce abduction and cause more esotropia on side gaze than in primary gaze position (“incomitant esotropia”). Bilateral third nerve palsy would cause an exotropia. Bilateral fourth nerve palsy would cause a right hypertropia in left gaze and a left hypertropia in right gaze, features not present here.