Which of the following is true about hydrocephalus?

A. Hydrocephalus is not a normal variation — it is a neurological disorder that requires medical attention. B. Hydrocephalus is caused by an increase, not a decrease, in cerebrospinal fluid (CSF) in the brain's ventricles. C. While inflammation (like meningitis) can lead to hydrocephalus, the condition itself is not defined by brain tissue inflammation. D. Hydrocephalus is characterized by an abnormal buildup of CSF in the brain’s ventricles, leading to ventricular enlargement and increased intracranial pressure. This can be due to obstruction, poor absorption, or overproduction of CSF.