The Cerebral Cortex Is Often Referred to as the Grey

The cerebral cortex is often referred to as the grey matter because of its colour. The area just below the cortex is often called white matter because of its colour. This area is white because

A) the axons of its neurons issulated with myelin which is white
B) this regions has fewer blood vessels which alters the overall colour.
C) the cell bodies of these neurons are chemically different a way that makes them a lighter colour.
D) Both regions are actually the same colour, this is just a convention that is used for clarity of discussion.