Which of the following statements refers to plicamycin (formerly mithramycin):
a) Duration of action is usually several days
b) Mechanism of cytotoxic action appears to involve its binding to DNA, possibly through an antibiotic-Mg2+ complex.
c) The drug causes plasma calcium levels to decrease, apparently through an action on osteoclasts that is independent of its action on tumor cells and useful in hypercalcemia.
d) All of the above.