Which would show an example of how physical changes are reversible?

cutting a gold bar in two pieces and then putting the pieces next to each other
burning a match and then relighting it
melting tin and then cooling it into a mold
combining sodium and chlorine to make the new material of table salt

Which would show an example of how physical changes are reversible cutting a gold bar in two pieces and then putting the pieces next to each other burning a mat class=