What characterizes Sudden Infant Death Syndrome (SIDS)?

Sudden Infant Death Syndrome (SIDS) is characterized primarily by the unexplained death of a seemingly healthy infant, typically occurring during sleep. This phenomenon occurs usually in infants aged one month to one year, and despite extensive investigation, there is often no clear cause that can be identified after post-mortem examinations. The term "sudden" is crucial here, as it underscores the unexpected nature of the event, and "unexplained" indicates that despite thorough medical evaluations, there is no identifiable medical condition or cause of death.

The other choices do not accurately reflect the characteristics of SIDS. Death after a prolonged illness suggests a known medical condition, while the notion of sudden death during an infant's first cry is not a recognized definition of SIDS. Additionally, deaths caused by infection would generally have identifiable causes, such as bacterial or viral infections, which is distinctly different from the phenomena described in SIDS cases. Therefore, the answer emphasizes the critical aspect that SIDS involves sudden, unexplained deaths in healthy infants, highlighting its tragic and distressing nature for families.