The correct option is D All of the above.
We need to use our resources carefully because these are not available forever, and with the human population increasing at a tremendous rate due to improvement in health care and other facilities, the demand for resources is increasing at an exponential rate. Also, as the consumption of fossil fuels like petroleum and coal hikes, the level of the release of harmful gases into the atmosphere increases. This needs to be controlled as it causes a potential threat to living species.