The correct option is D cerebrospinal fluid
The cerebral aqueduct is present within the midbrain. It contains cerebrospinal fluid (CSF). CSF acts as a shock absorber, cushioning the brain against the skull.
Lymph is the colorless fluid that flows through the lymphatic system. Endolymph is the fluid contained in the membranous labyrinth of the inner ear. Plasma is the clear, straw-colored liquid portion of blood that remains after red blood cells, white blood cells, platelets and other cellular components are removed.