Which of the following statements best describes the impact of a valuation allowance on the financial statements A valuation allowance:（）

A. increases reported income, reduces assets, and reduces equity.  

B. reduces reported income, reduces assets, and reduces equity.  

C. increases reported income, increases liabilities, and reduces equity.

估测产后出血量的方法有（）

A.称重法

B.容积法

C.面积法

D.休克指数法

E.心率减慢