Choosing materials

A soldering iron can reach a maximum temperature of $250\,^{\circ}\text{C}$. A student wants to choose a material for solder from the list: tin (melting point $232\,^{\circ}\text{C}$), aluminium ($660\,^{\circ}\text{C}$), lead ($327\,^{\circ}\text{C}$), and zinc ($420\,^{\circ}\text{C}$). Which material is most suitable based on melting point?