Each day computers help millions of people do their jobs more effectively. For example t

Each day, computers help millions of people do their jobs more effectively. For example, they can help managers decide on a future course of action, and they can then help with the follow-up checks on performance to see if planned goals are being achieved. By using accurate and timely facts supplied by data base management software, a manager can do a better job of identifying problems and opportunities. And managers may not need to spend as much time in controlling when a computer can respond with a triggered report if actual performance varies from what was planned. The time saved in controlling may allow managers to give more attention to employees" concerns, and this, in turn, may result in improved morale (士气).

But employment benefits certainly aren"t restricted to managers. Healthcare researchers and other scientists also use computers to conduct research into complex problem areas that couldn"t otherwise be studied. Lawyers use online legal data banks to locate precedent (先前的) cases in order to serve clients better. Salespeople can receive more timely information about products in stock, can promise customers that their sales orders will be handled promptly, and can thus improve their sales performance because of the computer system. And the job duties of some office and factory workers have changed from routine, repetitive operations to more varied and appealing tasks through computer usage. For example, office workers who understand text processing, computing, and data communication usually have vital roles and are given critical office functions to perform.

Which of the following examples shows the controlling function of a computer？

A．Helping managers decide on a future course of action.

B．Helping managers check if planned goals are reached.

C．Helping managers save time in writing a report.

D．Helping managers design a spreadsheet package.

请帮忙给出正确答案和分析，谢谢！