The correct answer is A. Paper.
Paper is a biodegradable material, meaning that it can be broken down by bacteria and other microorganisms. This process can take anywhere from a few weeks to several months, depending on the type of paper and the environment in which it is being decomposed.
DDT is a synthetic chemical that was once widely used as an insecticide. However, it is now known to be harmful to the environment and has been banned in many countries. DDT is not biodegradable and can remain in the environment for many years.
Aluminium is a metal that is not biodegradable. It can be recycled, but it cannot be broken down by natural processes.
Plastic is a synthetic material that is not biodegradable. It can take hundreds of years to decompose, and even then, it does not break down completely. Instead, it breaks down into smaller pieces that can be harmful to the environment.
In conclusion, the only biodegradable material among the options is paper.