Concept:Petrochemistry is the study of chemicals derived from petroleum and natural gas.
It uses chemical knowledge for industrial and practical purposes.
Explanation:Applied chemistry involves using chemical principles to solve real-world problems and produce useful materials.
Petrochemistry deals with refining crude oil and converting its products into fuels, plastics, and other chemicals.
Since it applies chemistry to practical industries, it is classified as applied chemistry.
It is not limited to the study of living systems, so it is not biochemistry.
It focuses on applications rather than fundamental theories, so it is not pure chemistry.
It is broader than only environmental concerns, so it is not environmental chemistry.
Answer:A. Applied chemistry