Most common cause of hydrocephalus in children is –

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 ".