Which part of the corpus callosum is located towards the rear end?

The splenium of the corpus callosum is indeed located towards the rear end of this structure. The corpus callosum is a large bundle of neural fibers that connects the left and right hemispheres of the brain, facilitating interhemispheric communication. It can be divided into sections, and the splenium represents the posterior or rear part of the corpus callosum. This area is particularly important for connecting the occipital lobes and is involved in visual processing, reflecting its proximity to the visual areas of the brain.

The other regions mentioned, such as the genu, are positioned at the front or anterior part of the corpus callosum, which would not make them suitable choices for identifying the rear portion. The primary motor cortex and primary visual cortex are not parts of the corpus callosum; rather, they refer to areas of the cerebral cortex associated with movement and vision, respectively, further confirming that the splenium is indeed the correct answer in this context.