根据信用证汇票条款，签发汇票：

Drawer: China National Chemicals Import & Export Corporation, S.B.

Drawee: The CITI Bank. New York, N.Y. , U. S. A.

Payee: to order of the Bank of China

Sum: US$ 1000.35

Date of issue: March 25,2006.

Tenor: at 90 days after sight

L/C No: DH006832SH

Issuing bank: The CITI Bank. New York, N. Y. , U. S. A.

Inv. No: SKYLN20050812

安全带应该高挂低用，挂钩应该扣在不低于作业者所处水平位置的（）牢靠处。

A、随意

B、安全

C、固定