A nurse is reviewing discharge instructions with the caregiver of a 3-year-old child who underwent nephrectomy for Wilms' tumor. Which statement by the caregiver best demonstrates understanding of the necessary activity precautions to protect the child's remaining kidney?

"My child can participate in noncontact sports like swimming as they row."

"I need to ensure my child avoids salty foods but there are no concerns about physical activity."

"Because my child has only one kidney, I will encourage increased physical activity to strengthen it."

"My child will be able to play boxing next year."