下列何者為應力（stress）的單位？
dyne/cm
dyne/(cm．\mathrm{sec}^{2})
\mathrm{sec}^{2}
g/(\mathrm{cm}^{2}．\mathrm{sec}^{2})
\mathrm{cm}^{2}
g/(cm．\mathrm{sec}^{2})
