The correct answer is option (3) as statement I is correct but statement II is incorrect. In human brain, a deep cleft divides the cerebrum longitudinally into two halves, which are termed as the left and right cerebral hemispheres. The cerebral hemispheres are connected by a tract of nerve fibres called corpus callosum. Three major regions make up the brain stem i.e. mid brain, pons and medulla oblongata. Cerebrum is a part of forebrain which does not form brain stem. Options (1), (2) and (4) are incorrect.