The scientific view is that the increase in global temperature should not exceed 2 °C above pre-industrial level. If the global temperature increases beyond 3 °C above the pre-industrial level, what can be its possible impact/impacts on the world? 1. Terrestrial biosphere tends toward a net carbon source. 2. Widespread coral mortality will occur. 3. All the global wetlands will permanently disappear. 4. Cultivation of cereals will not be possible anywhere in the world. Select the correct answer using the code given below.

Option (b) is correct because a temperature rise beyond 3°C triggers positive feedback loops where increased respiration and forest dieback turn the terrestrial biosphere into a net carbon source, while extreme thermal stress causes widespread, irreversible coral mortality. Option (d) is the most tempting wrong choice, but it is incorrect because statements 3 and 4 use extreme qualifiers ("all" and "anywhere") that are scientifically inaccurate, as some wetlands will persist and cereal cultivation may still be possible in higher latitudes. The core concept tested is the ecological thresholds of global warming and the ability to distinguish between severe impacts and absolute, hyperbolic generalizations.