The corpus callosum is comprised of more than 200 million axons that connect the hemispheres of the brain.

Indeed, the sentence is True.

The corpus callosum is a transverse commissure (means of union between two parts) of the brain present in placental mammals. It is a bundle of axons interconnecting the two cerebral hemispheres. It is the most important commissure of the brain because it connects the four lobes of the brain between them (frontal, temporal, parietal and occipital lobes left and right).

The corpus callosum thus ensures the transfer of information between the two hemispheres and thus their coordination. The other commissures are the fornix, the cingulum and the anterior white commissure.

the correct answer, according to e2020, is the second choice there is an occluded front in region a and a cold front in region b.