Hi. I don’t understand why the answer given is C. Why can’t I choose D?

Reaction of CH₃Cl and Cl₂ in presence of light as given in the question is an example of free-radical substitution reaction of alkyl halides with halogen.Reaction involves substitution of an halogen in place of hydrogen and removal of molecule of HCl step by step.
The answer given is C and not D.This can be understand as follows-
In one of the propogation step CH₂Cl^• is generated-
CH₃Cl^•+ Cl^•---------> CH₂Cl^•+ HCl
Now in termination step it is possible that CH₂ClCH₂Cl is formed in traces in the following manner-
2CH₂Cl^•---------> CH₂ClCH₂Cl