Which is true on the subarachnoid space in the vertebral canal（）。

• A、lies between dura matter and arachnoid
• B、up to subarachnoid space in the skull by the foramen magnum
• C、down the the height of the fifth sacral vertebral
• D、terminal cistern is formed by the space below the second sacral vertebral
• E、the fluid in it can communicate with that in the center canal of spinal cord directly