The correct answer is option 2, sublimation. Sublimation is a process where a solid directly changes into a gas without going through the liquid phase. Anthracene has a high vapor pressure, which means it can sublime at relatively low temperatures.

Option 1, distillation, is not suitable for separating anthracene from a mixture of salt and anthracene because distillation is typically used to separate liquids based on differences in their boiling points. Since salt does not boil, it cannot be separated using distillation.

Option 3, evaporation, involves the conversion of a liquid into a vapor by heating. While evaporation can be used to separate the solvent from the mixture, it cannot selectively separate anthracene from salt as they do not have significantly different boiling points.

Option 4, chromatography, is a separation technique based on differences in the affinity of components in a mixture for a mobile phase and a stationary phase. While it can be used for separating different compounds, it may not be effective for separating anthracene from salt.

Overall, sublimation is the most suitable method to selectively separate anthracene from a mixture of salt and anthracene.