Chlorination of methane in sunlight, where chlorine atoms replace hydrogen atoms one by one, is an example of which reaction?

1. Saturated hydrocarbons react with chlorine in the presence of sunlight. 2. Chlorine atoms take the place of hydrogen atoms one by one. 3. A reaction where one atom or group is replaced by another is a substitution reaction. 4. Rule out C: addition occurs at multiple bonds in unsaturated compounds, but methane is saturated. _Source: Balbharati (Maharashtra Board) Class 10 Science & Technology, Ch 9 "Carbon Compounds", p.135_