In the free radical substitution of methane by chlorine, which step has the lowest activation energy?
- A$\text{CH}_3\cdot + \text{Cl}_2 \rightarrow \text{CH}_3\text{Cl} + \text{Cl}\cdot$
- B$\text{Cl}\cdot + \text{Cl}\cdot \rightarrow \text{Cl}_2$
- C$\text{Cl}\cdot + \text{CH}_4 \rightarrow \text{CH}_3\cdot + \text{HCl}$
- D$\text{Cl}_2 \rightarrow \text{Cl}\cdot + \text{Cl}\cdot$