The 47-year-old obese bank teller presents for evaluation of lower extremity edema. She is otherwise healthy and has no other major medical problems. She has had problems with this for many years. On examination of her lower extremities, she has significant swelling of both lower extremities up to the knee. The skin is markedly thickened, nonpigmented, and nonpitting. There are no ulcers or evidence of previous ulcers. What is the likely source of this problem? Chronic venous insufficiency. Chronic lymphatic obstruction. Chronic arterial insufficiency. Venous thrombosis. Hypoalbuminemia.