Which substance can be easily adsorbed by charcoal?
Gas molecules bind to activated carbon as a result of London dispersion forces. Therefore, the larger the molecules, as determined by the size and the number of atoms in it, the better they bind to the carbon.

If you were to rank these in order of highest dispersion forces to lowest, that list would read: $$\ce{SO2&gt;CO2&gt;H2&gt;He}$$