Correct Option: B

In leaves of C₄ plants, malic acid synthesis during CO₂ fixation occurs in mesophyll cells. The mesophyll cells perform C₄ cycle and the cells of bundle sheath perform C₃ cycle. CO₂ taken from the atmosphere is accepted by phosphoenol pyruvic acid (PEP) present in the chloroplasts of mesophyll cells of these leaves, leading to the formation of a 4-C compound, oxaloacetic acid (OAA). This acid is converted to another 4-C acid, the malic acid which enters into the chloroplast of bundle sheath cells and undergoes oxidative decarboxylation yielding pyruvic acid (3C - compound) and CO₂.