I cannot______ puzzled, for I simply cannot understand how I could have made such a stupid mistake.

A．help feel

B．help but to feel

C．but to feel

D．help but feel

如果仲裁机构受理了A公司的仲裁申请，仲裁过程中A公司与B公司达成调解协议，可以( )方式结案。

A．仲裁庭根据调解协议制作裁决书

B．仲裁庭制作调解书

C．仲裁庭作出准许撤回仲裁申请的裁决书

D．撤回仲裁申请