下列属于国有建设用地使用权出让合同附件的是（）。

A.出让宗地竖向界限

B.土地使用期限

C.土地界址、面积

D.不可抗力的处理

VHF Radio is one of the very important navigational instruments on board，（）messages can be sent.

A.by which

B.through which

C.by that

D.through that