Which of the following is a free radical substitution reaction?

Options

1. ABenzene with ${Br}_{2} / {AlCl}_{3}$
2. BAcetylene with $HBr$
3. CMethane with ${Br}_{2} / hv$
4. DPropene with $HBr / {\left({C}_{6}{H}_{5}COO\right)}_{2}