<prompt> Most common cause of hydrocephalus in children isPost inflammatory obstructionBuddchiary syndromeBrain tumourPerinatal injury  <response>: Answer of this question is none because :-MC cause of obstructive non-communicating hydrocephalus -- aqueductal stenosis.MC cause of non-obstructive communicating hydrocephalus subarachanoid hemorrhage.But, amongst the given options best answer is option a.A common cause of acquired hydrocepahalus, is post inflammatory obstruction. Bacterial and tuberculous meningitis have a propensity to produce thick tenacious exudate that obstructs the basal cisterns . 