I, III only

I, II only

II, III only

I, II, III

$3: 1$

$2: 1$

$1: 2$

$1: 3$

$\mathrm{CHCl}_3$ - used in production of freon - 12.

$\mathrm{CCl}_4$ - used in production of freon - 22.

$\mathrm{CH}_2 \mathrm{Cl}_2$ - used as propellant in aerosols.

DDT - first chlorinated organic herbicide.