The right option is; d. all of the above
The ozone layer is a part of Earth's stratosphere that acts as a shield, absorbing most of the Sun's ultraviolet radiation. The ozone layer helps to sustain life on earth by filtering out or absorbing biologically damaging ultraviolet radiation from the sun. It controls the level of ozone in the lower atmosphere (troposphere). The ozone in the troposphere is harmful to humans because it can damage the lungs. The ozone layer also plays an important role in the Earth's temperature structure.
