Which of the following statements regarding hypercalcemia are true? A. The symptoms of hypercalcemia may mimic some symptoms of hyperglycemia. B. Metastatic breast cancer is an unusual cause of hypercalcemia. C. Calcitonin is a satisfactory long-term therapy for hypercalcemia. D. Severely hypercalcemic patients exhibit the signs of extracellular fluid volume deficit. E. Urinary calcium excretion may be increased by vigorous volume repletion.