Beth is a 16-year-old patient whose mother has brought her to the office because Beth is always complaining of being tired. Beth tells you that she has frequent headaches, and her feet are always cold. Her blood pressure is 100/64, and her heart rate is 84. When you ask if her menstrual periods are normal, she says she bleeds heavily for 7 or 8 days each month. Which of the following conditions might you suspect? Multiple Choice polycythemia vera iron-deficient anemia thalassemia leukemia sickle-cell anemia