Pre-supernova carbon mass fraction profiles of a single star (left semicircle) and binary-stripped stars (right circular sectors) with the same initial mass (M_ini) of 14 M_⊙ but different initial orbital periods at solar metallicity. The initial orbital periods are labeled outside each circular sector. The colors indicate the carbon mass fraction in logarithmic scale. From the outer envelope to the inner core, different layers are enriched in hydrogen, helium and carbon, oxygen, and iron, as labeled. Most of the carbon ejected by supernova explosions is contributed by the helium- and carbon-rich layer (dark green, remnant of helium shell burning) and the carbon-rich but helium-poor layer (light green, remnant of helium core burning).