《湖北省农村信用社财务管理办法（试行）》（鄂农信发[2013]21号）规定，业务招待费指为了拓展业务发生的与经营管理活动相关的招待费用，应据实列支，不得预提，严格控制在营业收入的千分之六以内。

In the following essay, each blank has four choices. Choose the best answer and write down on the answer sheet.

Microwave communication uses (1) -frequency radio waves that travel in straightline sthrough the air. Because the waves cannot (2) with the curvature of the earth, they can be (3) only over short distance. Thus, microwave is a good (4) for sending data between buildings in a city or on a large college campus. For longer distances, the waves must be relayed by means of" dishes" or (5) . These can be installed on towers, highbuildings, and mountain tops.

5（）

A．repeaters

B．radars

C．telephones

D．antennas