Concept:
Environmental studies is a multidisciplinary academic field that systematically studies human interaction with the environment. Its ultimate goal is not just to observe, but to preserve and enhance the natural world.
Step 1: Increasing industrial production (A) and promoting urbanization (D) are often the causes of environmental degradation, not the objective of studying it. While sustainable development balances these, they are not the primary goal of environmental science.
Step 2: Understanding environmental laws (B) is a tool used within the field, but it is far too narrow to be the "main objective" of the entire discipline.
Step 3: The fundamental purpose of studying the environment—understanding ecosystems, pollution, climate change, and resource depletion—is to figure out how to stop the damage.
Step 4: Therefore, the overarching main objective is to actively protect the existing environment from further harm and improve the quality of degraded environments.