Failure of closure of the cranial neural pore causes:
Correct Answer: A
Rationale: The failure of closure of the cranial neural pore leads to anencephaly due to the incomplete development of the brain and skull. This results in the absence of a major portion of the brain, skull, and scalp. Hydrocephaly (B) is the abnormal accumulation of cerebrospinal fluid within the brain's ventricles, not caused by the cranial neural pore closure. Hydrocephalus (C) is the same as hydrocephaly. Chiari malformation (D) is a condition where brain tissue extends into the spinal canal, unrelated to the cranial neural pore closure.