下列说法中，与敬业精神无关的是

A.不爱岗就会下岗，不敬业就会失业 

B.李素丽坚持“四心”服务原则：礼貌待客要热心，照顾乘客要细心，帮助乘客要诚心，热情服务要恒心 

C.如果你懂得量入为出，那你就可以致富了 

D.诚实的人必须对自己守信，他的最后靠山就是真诚 

Flow control is a function that prevents network congestion by ensuring that (59) do not overwhelm (60) with data.

There are three commonly used methods for handling network congestion. (61) is used by network devices to temporarily store bursts of excess data in memory until they can be processed (62) are used by receiving devices to help prevent their buffers from overflowing. (63) is a flow-control scheme in which the source device requires an acknowledgment from the destination aider a certain number of packets have been transmitted.

59（）

A．transmitting devices

B．transmitted devices

C．receiving devices

D．received devices