Pick the correct description of the brain. A. The gray matter of the cerebrum forms a surface layer called the nuclei and deeper masses called tracts surrounded by white matter. B. The gray matter of the cerebrum forms a surface layer called the medulla and deeper masses called cortex surrounded by white matter. C. The gray matter of the cerebrum forms a surface layer called the cortex and deeper masses called ganglia surrounded by white matter. D. The gray matter of the cerebrum forms a surface layer called the medulla and deeper masses called the midbrain surrounded by white matter. E. The gray matter of the cerebrum forms a surface layer called the cortex and deeper masses called nuclei surrounded by white matter.