The term "sixth mass extinction/sixth extinction" is often mentioned in the news in the context of the discussion of

1. A

   Widespread monoculture practices in agriculture and large-scale commercial farming with indiscriminate use of chemicals in many parts of the world that may result in the loss of good native ecosystems.

   (a) Monoculture and chemical farming. Industrial agriculture can erode local ecosystems, but “sixth extinction” in news is the broader Holocene/Anthropocene biodiversity collapse, not only farming systems. This option is not the key.

2. B

   Fears of a possible collision of a meteorite with the Earth in the near future in the manner it happened 65 million years ago that caused the mass extinction of many species including those of dinosaurs.

   (b) A future meteorite like the K–Pg impact. That is a possible future catastrophe and a past mass extinction driver, not the “sixth extinction” phrase used for present human-caused loss. This option is not the key.

3. C

   Large scale cultivation of genetically modified crops in many parts of the world and promoting their cultivation in other parts of the world which may cause the disappearance of good native crop plants and the loss of food biodiversity.

   (c) GM crops and food biodiversity. GM cultivation is a contested farming topic; it is not the standard meaning of sixth mass extinction. This option is not the key.

4. D

   Mankind's overexploitation/misuse of natural resources, fragmentation/loss of natural habitats, destruction of ecosystems, pollution and global climate change.

   (d) Overexploitation, habitat loss, ecosystem destruction, pollution and climate change. Scientists use “sixth extinction” for the current human-driven pulse of species loss, caused by those pressures together. That is the news context. This option is the official key.

Summary. Official key is (d). Five past mass extinctions were geological; the “sixth” in contemporary discussion is anthropogenic biodiversity collapse. Drivers named in (d)—overuse of resources, habitat fragmentation, ecosystem destruction, pollution and climate change—match that usage. Monoculture, a hypothetical meteorite, or GM crops are narrower or different stories. The Set A key is therefore (d).