有利于老年人健康的饮食原则，错误的是

A．摄入尽量多的蛋白质

B．多吃蔬菜、水果以增加维生素和膳食纤维的摄入

C．脂肪的摄入以植物油为主

D．糖类以谷类为主，少吃精制糖

E．经常吃豆类和鱼类食品

Flow control is a function that prevents network congestion by ensuring that (66) do not over-whelm (67) with data. There are three commonly used methods for handling network congestion. (68) is used by network devices to temporarily store bursts of excess data in memory until they can be processed. (69) are used by receiving devices to help prevent their buffers from overflowing. (70) is a flow-control scheme in which the source device requires an acknowledgment from the destination after a certain number of packets have been transmitted.

（69）是（）

A. Buffer

B. Source-quench messages

C. window

D. Windowing

E. Buffering