The correct answer is (c), maize.
C4 plants are a type of plant that uses a different pathway to produce sugar than C3 plants. This pathway is more efficient in hot, dry environments, and C4 plants are therefore more common in these areas. Maize, sugarcane, and sorghum are all examples of C4 plants.
Paddy (a) is a type of rice that is grown in flooded fields. Soya bean (b) is a legume that is grown for its beans. Wheat (d) is a cereal crop that is grown for its grain.
C3 plants use the Calvin cycle to produce sugar. The Calvin cycle is a series of reactions that take place in the stroma of chloroplasts. The Calvin cycle begins with the fixation of carbon dioxide into ribulose bisphosphate (RuBP). RuBP is a five-carbon sugar that is converted into 3-phosphoglycerate (3-PGA), a three-carbon sugar. 3-PGA is then converted into glyceraldehyde 3-phosphate (G3P), a five-carbon sugar. G3P is used to produce glucose, which is the plant’s main source of energy.
C4 plants use the Hatch-Slack pathway to produce sugar. The Hatch-Slack pathway is a series of reactions that take place in the mesophyll cells and bundle sheath cells of C4 plants. The Hatch-Slack pathway begins with the fixation of carbon dioxide into phosphoenolpyruvate (PEP). PEP is a three-carbon sugar that is converted into oxaloacetate (OAA), a four-carbon sugar. OAA is then converted into malate, a four-carbon sugar. Malate is transported to the bundle sheath cells, where it is decarboxylated to release carbon dioxide. The carbon dioxide is then fixed into RuBP, and the Calvin cycle begins.
The Hatch-Slack pathway is more efficient than the Calvin cycle in hot, dry environments because it allows the plant to concentrate carbon dioxide in the bundle sheath cells. This concentration of carbon dioxide increases the rate of the Calvin cycle.