无效合同的确认权属于（）。

A．建设行政主管部门

B．公证机关

C．工商行政部门

D．人民法院或仲裁机构

Chain suspension ladders on a ship must be replaced by fixed ladders if the required chain suspension ladder（）.

A.has been sent in for repair

B.cannot be supported against a vertical flat surface

C.does not extend to the water when the ship lists 15 degrees

D.is not equipped with vertical guard rails on either side