单选题：根据下面内容，回答题：Working an eight-hour day is a luxury for most p

根据下面内容，回答题：
Working an eight-hour day is a luxury for most professional people. Nowadays, the only way to guarantee an eight-hour working day is to have the kind of job where you clock on and off. Those professionals who have managed to limit their hours to what was, ~0 years ago, the average do not wish to identify themselves. "I can quite easily achieve my work within a normal day, but I don't like to draw attention to it," says one sales manager."People looked at me when I leave at 5 o'clock. Now, I put paperwork in my bag. People assume I'm doing extra hours at home. "
But more typical is Mark, who works as an account manager. He says, "My contract says I work from 9 until 5 with extra hours as necessary. It sounds as if the extra hours are exceptional. In fact, my job would be enough not only for me, but also for someone else part- time. The idea of an eight-hour day makes me laugh!" He says he has thought about going freelance but realizes that this doesn't guarantee better working hours.
Professors Cary Cooper, occupational psycholo- gist at the University of Manchester, is the author of the annual Quality of Working Life survey. The most recent survey found that 77% of managers in Britain work more than their contracted hours, and that this is having a damaging effect on their health, relationships and productivity. Professor Cooper is critical of the long-hours culture. He says that while bosses believe long hours lead to greater efficiency, there is no evidence to support this. "In fact, the evidence shows that long hours make you ill. "
There am, he says, steps that can be taken. One　is to accept that the in-tray will never be empty."There are always things to do. You just have to make the rule that on certain days you go home early. " Prioritising work and doing essential tasks first helps, he says. He also thinks it's time to criticize bad employers and unreasonable terms of employment. " By all means, show commitment where necessary but when expectations are too high, people have to begin saying openly that they have a life outside of work. "
Personal development coach Mo Shapiro agrees that communication is important. Staff need to talk to managers about the working practices within a company. Both parties should feel that the expectations are realistic and allow them to have responsibilities and interests outside work. She recongnises, however, that in many organizations the response might well be, "If you want more interests outside work, then find another job. "
She believes that senior staff have a duty to set an example. "I recently worked for a finn of solicitors where the partners started at 7:30 a. m. What kind of message is that to send to the staff?" She believes there is no shame in working sensible hours in fact quite the reserve."Some people might be in at 7. 30 am but will be doing very little. You can work really hard from9 to 5 and achieve the same. If you find it difficult to achieve an eight-hour day, there is, as a last resort, the old trick of leaving your jacket on your chair and your computers switched on, even after you have left the building. "

What does the writer say in the first paragraph about people who work an eight-hour　day? A．They are reluctant to admit to this.
B．They are disliked by their colleagues.
C．They are limited to certain professions.
D．They often catch up on work in the evenings.