B. Only B
Feedback The first sentence talks about how a change in climate and increasing population could lead to a food crisis. Statement A which talks about the opinion expressed by experts about how the growth in population will require increased production of food grains follows the first statement. Statement B which talks about the various factors which degrade soil fertility and leave the soil unsuitable for growing crops ideally precedes the last statement which talks about the consequences which this is likely to lead to. Therefore only A and B form a coherent paragraph along with the two given statements. C which can conclude the paragraph, can follow the last sentence but not precede it.