The correct option is D cytoplasm and stroma
In C4 plants, the primary CO2 acceptor is a 3-carbon molecule phosphoenol pyruvate (PEP) which is fixed by the enzyme PEPcase (PEP carboxylase). PEP is present in the mesophyll cells and hence PEPcase is present in the cytoplasm of the mesophyll cells.
CO2 is utilised for the carboxylation of RuBP in the presence of the enzyme RuBisCO (RuBP carboxylase-oxygenase), by the C3 cycle of photosynthesis. Hence RuBisCO is present in the stroma of the chloroplast in the bundle sheath cells.