The correct option is D CH3Cl <CH2Cl2<CHCl3<CCl4
Intermolecular forces of attractions increases as molecular mass increases. So, large amount of heat require to break strong intermolecular forces and thus boiling point increases.
Here, the order of molecular mass is as follows : CH3Cl <CH2Cl2<CHCl3<CCl4 and thus boiling point also increases in same order.
CH3Cl <CH2Cl2<CHCl3<CCl4.