All of the above
The fourth ventricle is the last ventricle in the cerebellum, its T shaped roof has three apertures that communicate with the subarachnoid space.
Foramen of magendi a median aperture is present dorsally in the roof, it communicates with the cisterna magna.
Foramen of luschka is a lateral aperture that is present on the right and left side.
It drains into the cerebellopontine angle cistern.