<prompt> The commonest cause of obstructive hydrocephalus in children isAqueductal stenosisDandy walker syndromeSubarachnoid hemorrhageTubercular meningitis  <response>: ETIOLOGY OF HYDROCEPHALUSCommunicatingnon-obstructiveNon-communicatingobstructivePostmeningiticAqueductal stenosisposthemorrhagicDandy-walkerChiari malformationChoroid plexus papillomaTuberculosisObstructive non-communicating hydrocephalus develops most commonly in children due to aqueductal stenosis.Non-obstructive hydrocephalus most commonly occurs due to subarachnoid hemorrhage which is usually a result of intraventricular hemorrhage in a preterm infant. 