11. 下圖的pulmonary vascular resistance，A、B、C線代表的是？ (A) A: Total vessel B: Extra-alveolar vessel C: Intra-alveolar vessel (B) A: Extra-alveolar vessel B: Intra-alveolar vessel C: Total vessel (C) A: Total vessel B: Intra-alveolar vessel C: Extra-alveolar vessel (D) A: Intra-alveolar vessel B: Extra-alveolar vessel C: Total vessel