Which of the following is effectively used instead of $DDT$?

Some halogen-containing compounds are useful in daily life. Some compounds of this class are responsible for the exposure of flora and fauna to increasing amounts of $UV$ light,which causes significant destruction. Name the class of these halocompounds. In your opinion,what should be done to minimize the harmful effects of these compounds?

In the past,which of the following substances was commonly used as a solvent for dry cleaning of clothes?

Chloral $+$ Chlorobenzene $\xrightarrow{\text{Conc. } H_2SO_4}$ product.
The product is :

Identify the correct set from the following:

The first chlorinated organic insecticide prepared is