下列属于原始凭证的是（）。

A、经费预（决）算报表及文件

B、经费决算（核销）通知书

C、经费开支发票

D、银行结算凭证

E、银行对账单

The incidence of this disease has been greatly reduced thanks to our health care program.()

A. seriousness

B. frequency of occurrence

C. mortality

D. cure rate