Which equation(s) could be part of the propagation stage in the radical substitution of butane, C4H10\text{C}_4\text{H}_{10}C4H10, with bromine, Br2\text{Br}_2Br2, to form bromobutane, C4H9Br\text{C}_4\text{H}_9\text{Br}C4H9Br?
- C4H9∙+Br2→C4H9Br+Br∙\text{C}_4\text{H}_9^\bullet + \text{Br}_2 \rightarrow \text{C}_4\text{H}_9\text{Br} + \text{Br}^\bulletC4H9∙+Br2→C4H9Br+Br∙
- C4H10+Br∙→C4H9∙+HBr\text{C}_4\text{H}_{10} + \text{Br}^\bullet \rightarrow \text{C}_4\text{H}_9^\bullet + \text{HBr}C4H10+Br∙→C4H9∙+HBr
- C4H10+Br∙→C4H9Br+H∙\text{C}_4\text{H}_{10} + \text{Br}^\bullet \rightarrow \text{C}_4\text{H}_9\text{Br} + \text{H}^\bulletC4H10+Br∙→C4H9Br+H∙