在管道配件中，用丝扣来连接两段公称直径相同的管子的是（）。

A.大小头

B.活接头

C.等径弯头

D.异径弯头

WLANs are increasingly popular because they enable cost-effective connections among people, applications and data that were not possible, or not cost-effective, in the past. For example, WLAN-based applications can enable fine-grained management of supply and distribution (1) to improve their efficienty and reduce (2) .WLANs can also enable entirely new business processes. To cite but one example, hospitals are using WLAN-enabled point-of-care applications to reduce errors and improve overall (3) care. WLAN management solutions provide a variety of other benefits that can be substantial but difficult to measure. For example, they can protect corporate data by preventing (4) through rogue access points. They help control salary costs, by allowing IT staffs to manage larger networks without adding staff. And they can improve overall network mananement by integrating with customers' existing systems, such as OpenView and UniCenter. Fortunately, it isn't necessary to measure these benefits to justify investing in WLAN management solutions, which can quickly pay for themselves simply by minimizing time-consuming(5) and administrative chores.

空白处（3）应选择（）

A.finance

B.patient

C.affair

D.doctor