The temperature at which a liquid changes into vapour at the atmospheric pressure is called its .

The SI unit of latent heat of fusion is _____.

$\mathrm{A}: \mathrm{J} {\mathrm{kg}}^{-1} \mathrm{B}: \mathrm{J} {\mathrm{g}}^{-1}$ (Enter your correct answer as $\mathrm{A}$ or $\mathrm{B}$)