What factor increases the risk of lead exposure in children?

The correct choice emphasizes the significance of housing conditions in relation to lead exposure in children. Living in older housing that may still have lead-based paint significantly increases the risk of lead exposure. Many homes built before 1978, when lead paint was banned for residential use in the United States, still contain lead paint that can chip, peel, or create dust, all of which can be ingested or inhaled by children. Since young children are particularly susceptible due to their tendency to put objects in their mouths and their developing bodies, the presence of lead paint in older homes poses a serious health risk.

Other factors, such as living in rural areas or engaging in outdoor activities like visiting parks, generally do not carry the same level of risk for lead exposure relative to the condition of the housing. Similarly, while participation in sports activities is beneficial for physical health, it does not directly correlate with an increased risk of lead exposure. Thus, the age and painted conditions of housing remain the most critical factor affecting children's exposure to lead.