Inner and outer region of butterfly shaped area of spinal cord respectively consists of :
White matter, grey matter
Grey matter, white matter
Non- myelinated nerve fibres, myelinated nerve fibres
Both B and C
In grey matter, non myelinated nerve fibres are present inside butterfly shaped areas. Non myelinated nerves are grey in color. The grey matter is surrounded by white matter of the spinal cord called fasciculi and white column.
Hence, option 4 is the correct answer.