Which of the following has minimum melting point?

Ionic compounds have high melting point. Greater the ionic character, more is melting point. $\mathrm{HCl}$ has least ionic character because of maximum electronegativity difference between the two constituent elements, ( $\mathrm{H}$ and $\mathrm{Cl}$ ) among $\mathrm{CsF}, \mathrm{HCl}, \mathrm{HF}$ and $\mathrm{LiF}\therefore \mathrm{HCl}$ has minimum melting point.