氢氧化钠溶液中滴入酚酞试液会变红色，氢氧化钠溶液中主要含有Na⁺、OH^-、H₂O分子。某探究小组为探究氢氧化钠溶液中的哪种微粒能使酚酞试液变红，设计了如下实验方案，得出了初步结论。

（1）请填写下表中的实验结论：

（2）是否需要做“向水中滴加酚酞试液”的对比实验？为什么？

An internet is a combination of networks connected by (1). When a datagram goes from a source to a  (2), it will probably pass many (3) until it reaches the router attached to the destination network. A router receives a  (4) from a network and passes it to another network. A router is usually attached to several networks. When it receives a packet, to which network should it pass the packet? The decision is based on optimization: Which of the available (5) is the optimum pathway?

空白（4）处应选择（）

A.destination

B.resource

C.packet

D.source