An integral part of a blowout preventer that serves as the closing element on an open hole，and whose ends do not fit around the drill pipe but seal against each other and shut off the space below completely is the（）.

A.shear ram

B.blind ram

C.pipe ram

D.annular ram

党政机关、国有企业和事业单位以及金融机构党员的教育培训，每年至少一次，时间一般不少于（）学时。

A、12

B、24

C、36

D、48