What are the primary risk factors for sudden infant death syndrome (SIDS)?

The primary risk factors for sudden infant death syndrome (SIDS) include sleeping on stomachs, exposure to smoke, and overheating while sleeping. Research has shown that placing infants on their stomachs or sides significantly increases the risk of SIDS due to the potential for airway obstruction and re-breathing exhaled carbon dioxide. Exposure to tobacco smoke, either during pregnancy or after birth, is another critical risk factor, as it has been linked to respiratory issues and reduced arousal responses in infants, making them more susceptible to SIDS. Overheating, which can occur from excessive bedding, clothing, or a hot sleep environment, is also a notable risk since it may impair an infant’s ability to regulate their own body temperature and disturb sleep patterns.

Other options include risk factors or practices that either do not correlate with SIDS or are actually recommended strategies to reduce the risk. Using pacifiers and placing infants to sleep on their backs are associated with a decreased risk of SIDS, and the same applies to avoiding soft toys and loose bedding in the infant's sleep area. Thus, the practices outlined in option A directly relate to well-documented risks for SIDS, making it the correct choice.