The patient has :-Right superotemporal quadrantanopia Left superotemporal quadrantanopia Left centrocecal scotoma → Left optic nerve involvement e.g. toxic opic neuropathyIt has also been explained that early central chiasmatic lesion due to pituitary adenoma can cause upper temporal quadrantanopia. So, best answer here is 'a' i.e. left optic nerve with optic chiasma.