Which sleep stage is most closely associated with tissue healing and physical restoration?

A. Stage one sleep is a light transitional sleep phase and does not significantly contribute to tissue repair. B. REM sleep is important for memory consolidation and emotional processing, but not primarily for physical restoration. C. Stage two sleep is deeper than stage one but still not the stage most associated with healing and restoration. D. Stage three slow wave sleep; also known as deep sleep, it is when the body focuses on tissue repair, immune function, and physical restoration.