建筑行业的A公司向社会招聘具有较高资质的设计师，张某前去应聘，并出示了高级建筑师的执业证书，双方相互满意。
由于A公司对执业证书的管理缺乏经验，因此与张某协商：由A公司的协作单位B公司与张某签订劳动合同并管理执业证书，张某则在A公司工作，张某同意了A公司的要求。
半年后，张某发现B公司没有为自己缴纳社会保险费，于是就向B公司提出，B公司表示因张某为A公司工作，B公司无义务为其缴费。张某向A公司提出，A公司表示因张某的劳动关系不在A公司，A公司无法为其缴费。张某无奈之下只得向劳动仲裁委员会申请仲裁。
张某应当以何公司作为被诉人？理由？
参考答案：
张某应当以B公司作为被诉人行使主张，理由如下：
张某与B公司签订了劳动合同，虽然实际劳动权利义务与A公司发生，但是B公司应当履行社会保险缴费义务。
张某与B公司关于缴纳社会保险费争议属于劳动争议。
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| In l 901,the citizens of Colorado Springs in the USA decided to collect everydav items and to seal them in a steel box. The box was marked "To be 1 after midnight, December 31. AD 2000", and was 2 in the Colorado College Library. One hundred years later, on the appointed day,300 people 3 to watch the opening of the box? Many in the 4 were the descendants of people who had placed thillgs 5 the box. When the box was opened 6 midnight, the contents were in very good 7 .There were newspapers, photographs, diaries, name cards, family trees, books 8 dozens of letters, including one 9 by Theodore Roosevelt, who became the 10 of the USA later. One of Roosevelt's friends lived in Colorado Springs at that time. Many of the letters were 11 to their descendants. They describe the 12 that people of l 901 had for the people of the next 13 . At that time, Colorado springs had j ustl a few thousand 14 . Now nearly half a million people live there. Colorado College Library has scanned the materials and put them on a 15 . Cecil Muller, whose grandfather had 16 a collection of postcards in the box, said that the time capsule was a great 17 . "This is a wonderful educational resource. We can learn so 18 about our history," he said."I never knew my grandfather, but now I feel very 19 to him." In April, 2001,a committee filled the time capsule with 20 from modern Colorado Springs and resealed it for another hundred years. | ||||
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