The correct option is D Red blood cells
During the process of maturation of red blood cells (RBCs), they loose various cell organelles including nucleus, ER and mitochondria. This happens so that the RBCs can acquire a biconcave shape and accommodate more haemoglobin. This facilitates better transport of O2 in the body. Loss of mitochondria also ensures that the RBCs won’t be able to perform cellular respiration since Krebs cycle and electron transport chain occur in the mitochondria.