On heating with chlorine, the hydrocarbon 2,2-dimethylbutane reacts by free radical substitution. In a propagation step, the free radical X• is generated: $\text{(structure)} + \text{Cl}• \rightarrow X• + \text{HCl}$ How many distinct forms of X• can be produced?
- A1
- B2
- C3
- D4