74.磷脂酸肌醇-4,5-雙磷酸(phosphatidylinositol-4,5-bisphosphate, PIP2)水解產生用以促進細胞質中 Ca 濃度增加的第二訊息傳遞物是下列何者？ (A)二酸甘油酯(diacylglycerol, DAG) (B)磷脂酸肌醇(phosphatidylinositol, PI) (C)磷脂酸肌醇-4,5-雙磷酸 (D)1,4,5-三磷酸肌醇(inositol 1,4,5-trisphosphate, IP3)