A. Removing old paint chips and repainting the walls with lead-based paint can increase lead exposure. Lead-based paint should be safely removed by professionals following guidelines to prevent contamination.

B. Allowing the toddler to play in areas where renovations involving lead-based paint are ongoing is dangerous. Lead exposure can occur through contact with lead dust and particles during renovations.

C. Providing a diet rich in iron and calcium can help minimize lead absorption, but it does not replace the need for preventive measures to reduce exposure to lead.

D. Regularly cleaning the toddler's toys and hands reduces contact with lead dust, a common source of lead exposure. Handwashing and maintaining a clean environment are essential for lead prevention.