The answer is "c. Ozone in the troposphere is beneficial to living organisms."
because options a, b and d are true about ozone layer.
Ozone layer is the area of the upper atmosphere, between around 15 and 35 km over Earth's surface, containing generally high groupings of ozone particles (O₃). Roughly 90 percent of the environment's ozone happens in the stratosphere. The ozone layer successfully squares all sun oriented radiation of wavelengths under 290nm from achieving Earth's surface, including certain kinds of UV and different types of radiation that could harm or kill most living things.