The correct option is B LiCl>NaCl
As we move down the group, lattice energy decreases and hence the melting point decreases. However, LiCl has some covalent character due to the polarization of Cl− by Li+. Hence, it has lower melting point.
Hence, the correct order of melting points of the given alkali metal chlorides is
NaCl>KCl>LiCl.