Answer is B (Renal Parenchymal Disease): Renal Parenchymal Disease is the most contmon cause of hypeension in children and should be considered in the evaluation of all asymptomatic children with hypeension Coarctation of Aoa may present with hypeension in children but this is an uncommon cause and usually presents with a charachteristic finging of blood pressure differential of > 10 mm Hg between upper and lower extremities, systolic hypeension in upper extremity along with decreased or absent femoral pulses Polycystic kidney Disease does not usually present with hypeension in children. Hypeension usually becomes clinically apparent in middle age and hence the condition is also called 'Adult' polycystic kidney disease.