GMAT Critical Reasoning (CR) | Re: To counter the escalating violence of inner cities, I

(C) a rise in violent crime and violence can be the result of the availability of firearms to ex-criminals

(D) most ex-criminals who purchase guns do so illegally

Pleaseexplain

VeritasPrepKarishma

I think both C and D strengthens the argument.
I m not being able to completely agree with any of the explanations in this thread.
Need expert opinion