The correct option is D Photorespiration
RUBISCO has affinity for both oxygen and carbon dioxide. Photorespiration is oxidation of RuBP, rather than carboxylation, by enzyme RUBISCO and formation of 2-phosphoglycolate. Under standard 25°C, the rate of the carboxylation reaction is four times that of the oxidation reaction and 20% of fixed carbon is lost in photorespiration. Spatial separation of carbon dioxide fixation and RUBISCO activity in mesophyll and bundle sheath cells of C4 plants respectively avoids photorespiration by concentrating CO2 in bundle sheath cells to scale down the oxygenase activity of RUBISCO and increase the RUBISCO efficiency which is not the case in C3 plants. Correct answer is D.