Explanation

(c)
Chloroform is oxidised by air in the presence of light to form phosgene or carbonyl chloride which is poisonous gas.
$CHCl_{3} + \frac{1}{2}O_{2}\underset{light\ }{\overset{\ \ \ \ \ \ \ Air\ \ \ \ \ \ \ }{\rightarrow}}COCl_{2} + HCl$
Chloroform phosgene