The correct option is
D Denucleated
The blood cells are of three major types they are erythrocytes(RBC), leucocytes(WBC) and platelets. Platelets or thrombocytes are cell fragments produced from megakaryocytes (special cells in the bone marrow). Formation of platelets by fragmentation of megakaryocytes in bone marrow is known as thrombopoiesis. As blood platelets are cell fragments they do not have any nucleus i.e Denucleated.So, the correct answer is 'Denucleated'.