I decided to go to the library as soon as I ______.

A．finished what I was doing

B．finished what I did

C．would finish what I was doing

D．finish what I did

甲向乙借款，将自己的汽车出质给乙做担保。双方签订了质押合同，但甲未将汽车交付给乙。后甲又向丙借款，丙要求甲提供担保，甲将该汽车又质押给丙，双方签订了质押合同，并将汽车交付给丙。丙因违章驾驶该汽车，致该汽车损坏。乙请求甲交付汽车，甲告知汽车在丙处。乙便向丙要车，丙不给。乙、丙双方发生纠纷。根据上述案情，请回答：

丙在占有质物期间违反了质权人应承担的何种义务？