$\mathrm{A}={\mathrm{CH}}_3\mathrm{Br},\mathrm{B}={\mathrm{CHBr}}_3,\mathrm{C}={\mathrm{CH}}_3\mathrm{Cl},\mathrm{D}={\mathrm{CH}}_2{\mathrm{Br}}_2$ correct order of boiling point 

As the number of halogen atoms increases boiling point increases

${\mathrm{CBr}}_4>{\mathrm{CHBr}}_3>{\mathrm{CH}}_2{\mathrm{Br}}_2>{\mathrm{CH}}_3\mathrm{Br}$

As the size of halogen atom increases boiling point increases

In general $\therefore {\mathrm{CH}}_3\mathrm{Br}>{\mathrm{CH}}_3\mathrm{Cl}$

As Molecular weight of a compound increases, boiling point  increases