Which one of the following statements about part-time work can be inferred from the information presented in the passage? A. One-third of all part-time workers are working mothers. B. Part-time work generally offers fewer opportunities for advancement to working mothers than to women generally. C. Part-time work, in addition to having relatively poor wages, often requires that employees work during holidays, when their children are out of school. D. Part-time employment, despite its disadvantages, provides working mothers with an opportunity to address some of the demands of caring for children. E. Many mothers with primary child-care responsibility choose part-time jobs in order to better exploit full-time career opportunities after their children are grown.