A ball is dropped from a height of 1000 Km .Due to heat from air friction & melts just before reaching the ground . The latent heat of fusion of ball's material is - (specific heat of material =100 $\;{J kg^{-1}}^{0}C$ Air tempeature=$\;25^{0}C\;$ , Melting point =$\;{J kg^{-1}}^{0}C\;$)

Question

$(a)\;9.1\;MJkg^{-1}\qquad(b)\;9.3\;MJkg\qquad(c)\;9.7\;MJkg^{-1}\qquad(d)\;None\;of\;these$