A nurse is caring for a client who has metabolic alkalosis. Which of the following assessment findings is a possible cause for this condition? (Select all that apply.)

A) History of vomiting
B) Serum potassium level 4.8 mg/dL (3.5 to 5 mg/dL)
C) Polycythemia
D) Blood urea nitrogen (BUN) 25 mg/L (10 to 20 mg/dL)
E) Overuse of antacids