Propane reacts with bromine in the presence of ultraviolet radiation to form a mixture of organic products. Which equation shows a propagation step in the mechanism for this reaction?
Br2→⋅Br+⋅Br\text{Br}_2 \rightarrow \cdot\text{Br} + \cdot\text{Br}Br2→⋅Br+⋅Br
⋅Br+⋅C3H6Br→C3H6Br2\cdot\text{Br} + \cdot\text{C}_3\text{H}_6\text{Br} \rightarrow \text{C}_3\text{H}_6\text{Br}_2⋅Br+⋅C3H6Br→C3H6Br2
C3H7Br+⋅Br→C3H6Br2+⋅H\text{C}_3\text{H}_7\text{Br} + \cdot\text{Br} \rightarrow \text{C}_3\text{H}_6\text{Br}_2 + \cdot\text{H}C3H7Br+⋅Br→C3H6Br2+⋅H
⋅Br+C3H7Br→⋅C3H6Br+HBr\cdot\text{Br} + \text{C}_3\text{H}_7\text{Br} \rightarrow \cdot\text{C}_3\text{H}_6\text{Br} + \text{HBr}⋅Br+C3H7Br→⋅C3H6Br+HBr
