The correct answer is D. All of the above.
Sustainable development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs. It is a broad concept that encompasses economic, social, and environmental dimensions.
Intergenerational equity is the principle that the current generation should not use up resources in a way that leaves future generations unable to meet their own needs. Intragenerational equity is the principle that the benefits and burdens of development should be shared fairly within the current generation. Extrageneration equity is the principle that humans have a responsibility to protect the environment for the sake of other species.
All three of these principles are important aspects of sustainable development. Without intergenerational equity, future generations would be left to deal with the consequences of our current unsustainable practices. Without intragenerational equity, the benefits of development would be concentrated in the hands of a few, while the burdens would be borne by the many. And without extrageneration equity, we would be putting the entire planet at risk.
Sustainable development is a complex challenge, but it is one that we must address if we want to ensure a bright future for all.