Which equation represents a termination step?
CH3CH3+Cl∙→CH3CH2∙+HCl\text{CH}_3\text{CH}_3 + \text{Cl}^\bullet \to \text{CH}_3\text{CH}_2^\bullet + \text{HCl}CH3CH3+Cl∙→CH3CH2∙+HCl
CH3CH2∙+O2→CH3CH2OO∙\text{CH}_3\text{CH}_2^\bullet + \text{O}_2 \to \text{CH}_3\text{CH}_2\text{OO}^\bulletCH3CH2∙+O2→CH3CH2OO∙
CH3CH2∙+CH3∙→CH3CH2CH3\text{CH}_3\text{CH}_2^\bullet + \text{CH}_3^\bullet \to \text{CH}_3\text{CH}_2\text{CH}_3CH3CH2∙+CH3∙→CH3CH2CH3
Br2→2Br∙\text{Br}_2 \to 2\text{Br}^\bulletBr2→2Br∙