Answer:
The correct option is A) green belts
Step-by-step explanation:
Environmental stressor can be described as any thing in the environment which will have the ability to cause stress.
A green belt can be described as a vast land around a city in which building anything is restricted. It is a good and positive approach for planning as it limits urban sprawling. Hence, option A is correct.
Other options, like earthquakes, toxic substances and high noise levels are environmental stressors.