硝酸甘油舒张血管平滑肌的机制是（）。

A.激活腺苷酸环化酶，增加cAMP

B.直接作用于血管平滑肌

C.激动β₂体

D.体内代谢生成NO

E.阻断Ca₂₊道

Which of the following choices most accurately illustrates an operating liability and which most accurately illustrates a financing liabilityOperating liabilities Financing liabilities（）

A. Customer advances        Accrued liabilities 

B. Short-term note payable     Current portion of long-term debt

C. Accounts payable        Current portion of long-term debt