Scores of workers from MTV Networks walked off the job yesterday afternoon, filling the sidewalk outside the headquarters of its corporate parent, Viacom, to protest recent changes in benefits. The walkout highlighted the concerns of a category of workers who are sometimes called permalancers: permanent freelancers who work like full-time employees but do not receive the same benefits.

Waving signs that read "Shame on Viacom," the workers, most of them in their 20s, demanded that MTV Networks reverse a plan to reduce health and dental benefits for freelancers beginning On Jan. 1st. In a statement, MTV Networks noted that its benefits program for full-time employees had also undergone changes, and it emphasized that the plan for freelancers was still highly competitive within the industry. Many freelancers receive no corporate benefits. But some of the protesters asserted that corporations were competing to see which could provide the most mediocre health care coverage. Matthew Yonda, who works at Nickelodeon, held a sign that labeled the network "Sick-elodeon. " "I’ve worked here every day for three years-I’m not a freelancer," Mr. Yonda said. "They just call us freelancers in order to bar us from getting the same benefits as employees. "

The changes to the benefits package were announced last Tuesday. Freelancers were told that they would become eligible for benefits after 160 days of work, beginning in January. While that eased previous eligibility rules, which required freelancers to work for 52 weeks before becoming eligible, it would have required all freelancers not yet eligible for benefits to start the waiting period over again on Jan. 1st. The 401 (k) plan was also removed. On Thursday, acknowledging the complaints, MTV Networks reinstated the 401 (k) plan and said freelancers who had worked consistently since March would be eligible.

Fueled by a series of blog posts on the media Web site Gawker-the first post was headlined "The Viacom Permalance Slave System"-a loose cohort of freelancers created protest stickers and distributed walkout fliers last week. Caroline O’Hare, a unit manager who has worked for MTV for more than two years, said the new health care plan-with higher deductibles and a $ 2,000 cap on hospital expenses each year-had provoked outrage. "They think they can treat us like children that don’t have families, mortgages or dreams of retirement," she said.

Outside Viacom’s headquarters, several workers held posters with the words, "There’s too many of us to ignore. " It was unclear how many freelancers are on the company’s payroll; an MTV Networks’ spokeswoman said the figure was not known because it rises and falls throughout the year. The company has 5,500 full-time employees, excluding freelancers, around the world.

Two freelancers and one full-time employee, who asked not to be identified for fear of retribution, estimated that the percentage of freelancers in some departments exceeded 75 percent. Another labor action is expected to take place outside Viacom later this week. Members of the Writers Guild of America, who have been on strike for five weeks, are expected to picket there on Thursday.

Why did the MTV Networks’ spokeswoman say the number of freelancers was unclear（）

A. The figure rises and falls all over the year

B. The company wants to keep it as a secret so that they can better stand the protest

C. As they are only freelancers, their payrolls are not included in the financial system of the company

D. They do not want to treat freelancers the same as full-time employees