Free radical reaction|oxymercuration of alkene|chain propagation steps

Free Radicals Addition Reaction

Free Radical Substitution Reactions

In the free-radical chlorination of methane, the chain-intiation step involves the formation of:

Arrange the following steps according to the order followed in the free radical mechansm for halogenation of alkanes ? I. Chain initiatinf step II. Chain termination step III. Chain propagation step