Questions 88-90 refer to the following advertisement. Obese people are less productive in the workplace and more prone to injury, a study claims. The researchers say their findings were so extreme that overweight people may need to take longer breaks to recover from the strains of work. They assessed how long it took for people of various sizes to perform certain tasks in the workplace. Obese people had, on average, 40 per cent shorter endurance times. The study, conducted at Virginia Tech and the University at Buffalo in the U.S., examined the endurance of 32 people in four categories: non-obese young, obese young, non-obese older, and obese older. Each of them completed three tasks that involved a range of skills: hand grip, shoulder elevation, and a simulated assembly operation. Every task involved periods of work and rest, and included a level of activity similar to manufacturing settings. The number of people who are obese has doubled over the past three decades-and has been linked to higher rates of workplace injury and a greater number of days of sick. ‘Workers who are obese may need longer rest breaks to return to their initial state of muscle function,’ said Dr Cavuoto. Based on the increased fatigue found among workers who are obese, workplace designers may need to consider adding fixtures and supports to minimize the amount of time that body mass segments need to be supported. ‘We believe our results will help to develop more inclusive ergonomic guideline,’ she added. The researchers also looked at the effect of obesity and age on endurance times. Previous research has indicated that both age and obesity hamper mobility-particularly when it comes to walking and low-energy tasks. But the researchers in this study, published in the Journal of Occupational and Environmental Hygiene, found no such link. What does the “ergonomic guideline” （paragraph 3） mean?
A. guidelines aimed at improving working conditions B. guidelines aimed at helping people lose weight C. guidelines aimed at improving working efficiency D. guidelines aimed at reducing the workload