Which health teaching concept should the nurse emphasize when instructing the parents of a child with polycythemia caused by a congenital heart disorder?

A. Seizures are not a typical complication of polycythemia, though they may occur if the condition progresses to severe levels of blood viscosity. B. Yellowing of the skin (jaundice) is not associated with polycythemia but with liver conditions. C. While activity is important, preventing dehydration is more critical in managing polycythemia because dehydration increases blood viscosity, exacerbating the condition. D. Preventing dehydration is essential as it helps maintain adequate blood flow and reduces the risk of thrombotic events in a child with polycythemia.