---We’d like a standard room, please.

---I’m sorry. All but two single rooms with Internet access        .

A．were reserved

B．has been reserved

C．have been reserved

D．has reserved

下列哪个项目属于机械完整性的范畴（）。

A.项目设计

B.项目施工

C.工艺变更

D.设计变更