Coordination compounds have great importance in biological systems. In this context which of the following statements is incorrect:
A. Chlorophylls are green pigments in plants and contain calcium.
B. Haemoglobin is the red pigment of blood and contains iron.
C. Cyanocobalamin is `B_(12)` and contains cobalt.
D. Carboxypeptidase-A is an enzyme and contains zinc.
