Researcher roger sperry won a nobel prize for his research on epilepsy. sperry cut through the which joins the two hemispheres of the brain.

Corpus callosum

Explanation:

The cerebral cortex is a region of the gray matter of the brain and is present in folded form. The grooves between the folds form fissure. The longitudinal fissure of the cerebral cortex is the biggest one and separates the cerebrum into two cerebral hemispheres. Corpus callosum is made up of white matter. The two cerebral hemispheres are connected internally by the corpus callosum.  During his research on the treatment of epilepsy, Roger Sperry cut the corpus callosum.

i think it’s c but i might be wrong. if i am let me know! have a good rest of your day as well!