Maximum CO2 is seen in-

Ans. is 'b' i.e., Pulmonary artery o Pulmonary arteries carry deoxygenated blood (with maximum CO2) to lung from right ventricle,o In lung CO2 is removed and oxygenation of blood takes place.o Pulmonary veins, then, transport this oxygenated blood (with less CO2) to the left atrium.